GIFT   OF 


v ''-"•*>     •• 


THE  AUTHOR 


Geological  Notes 

on  Oil  Structures 


Edward  Allison  Hill 

Consulting  Geologist 

cAuthor  of 
"Geological  Story  of  the  Mid-Continent  Oil  Fields" 


Hall-Gutstadt  Company,  Publishers 
San  Francisco,  1922 


CONTENTS 

Page 

CHAPTER          I— A  Glance  at  Early  Oil  Fields  in  Cali- 
fornia, and  Mention  of  Other  Regions  9 

CHAPTER        II— The  Organic  Shales  of  California 14 

CHAPTER      III — Remarks   about    Identification   of  De- 
posits and  Determination  of  Age,  and 

the  Use  of  That  Knowledge 21 

CHAPTER       IV — Relating    to    Oil    Structures    and    the 

Methods  of  Determining  Them 30 

CHAPTER        V— Some  Types  of  Oil  Structure  and  Re- 
marks About  Their  Character  in  Some 

Weil-Known  Fields 34 

CHAPTER      VI— Oil    Accumulation    Areas,    How    De- 
termined     45 

CHAPTER     VII— Summary,   Probable  New  Fields 55 

CHAPTER  VIII— Notes  on  Oil  Company  Promotion  and 

Related   Subjects    64 

Personal    Letter   to   the   Author   from 

George  H.  Hook,  Geologist 75 

CHAPTER       IX— Tarrant    County    Geological    History 

Revealed  by  Drill 76 

LIST  OF  ILLUSTRATIONS 

Page 

Cuts  Nos.   1   and  2 16' 

The    Illustration    Explained 17 

Cut    No.   3 28 

Explanation    29 

Cut  No.  4. 38 

Explanation    39 

Cut    No.    5 50 

Explanation     51 

Cut  No.  6 56 

Explanation    57 

Cut  No.  7 62 

Explanation    63 


INTRODUCTORY 

object  of  this  booklet  is  to  review  some  of  the  relative 
1  facts  incident  to  the  oil-producing  industry  of  California  and 
other  States;  to  suggest  some  of  the  conditions  existing  in 
formations;  the  character  and  methods  of  determining  the  bet- 
ter known  types  of  oil  structures;  afnd  the  possibilities  of  dis- 
covering additional  areas  where  oil  in  commercially  profitable 
quantity  may  be  found. 

As  viewed  from  the  standpoint  of  the  technical  geologist,  it 
is  not  altogether  easy  to  put  the  matter  in  a  form  to  be  quickly 
and  fully  visualized  by  the  lay  reader.  The  difficulty  is  not 
found  to  be  present  in  the  substance  to  be  embraced,  but  in 
accurately  knowing  what  to  leave  out  and  still  maintain  com- 
plete and  understandable  text  regarding  the  subjects  treated. 
If  it  seems  that  some  aspects  of  certain  of  the  items  chosen  by 
the  writer  for  inclusion  herein  are  scantily  discussed,  or  upon 
the  other  hand  if  too  much  space  appears  to  have  been  devoted 
to  some  other  thing,  it  will  be  remembered  that  there  are  many 
sources  of  data  of  extremely  various  kinds  of  an  historical,  com- 
mercial, geological  and  economic  character,  which  are  drawn 
upon.  The  mass  of  information  which  has  developed  regard- 
ing petroleum,  drilling,  producing,  marketing  and  other 
branches  of  the  industry,  and  the  literature  covering  the  cog- 
nate subjects  is  so  vast  that  the  difficulty  in  treating  any 
department  of  the  oil  business  briefly  is  in  knowing  what  to 
omit,  not  what  to  retain. 

Since  the  Geological  Departments  of  various  of  the  States, 
the  United  States  Geological  Survey,  and  other  public  and  pri- 
vate interests,  publish  many  able  and  trustworthy  bulletins, 
reports  and  other  papers  fully  setting  forth  the  statistics  of  the 
fields,  as  to  barrels  of  production,  value  in  money,  analyses  of 
the  different  grades  of  petroleum  and  other  detailed  and  reli- 
able information  of  that  general  type,  it  appears  needless  to 
t  repeat  that  matter  here.  Referring  particularly  to  California, 
it  is  and  has  been  for  many  years  one  of  the  chief  oil-producing 
regions  of  the  United  States.  The  names  of  its  principal  fields 
are  almost  as  well  known  to  the  general  public  as  are  the  loca- 
tions and  names  of  its  leading  cities:  Kern,  Taft,  McKittrick, 

7 

500561 


Sunset,  Coalinga,  Westside,  Eastside,  Oil  City,  Lost  Hills, 
Whittier,  Ventura — every  one  of  these  and  others  are  names 
almost  as  common  as  the  terms  employed  to  designate  the 
articles  in  our  living  rooms.  To  the  people  of  California  the 
names  of  these  fields  are  familiar  not  only,  they  are  known  to 
millions  of  men  that  have  never  even  been  in  the  State.  Their 
oil  output  has  a  cash  value  which  is  measured  in  hundreds  of 
thousands  of  dollars  every  week  and  a  potential  economic  worth 
doubtless  almost  wholly  beyond  estimation.  Kern  County 
alone  produces  over  one-tenth  of  the  total  petroleum  output 
of  the  United  States,  though  oil  of  higher  gravity  and  in  great 
quantities  is  annually  produced  in  the  Coalinga  and  other 
districts. 

THE  AUTHOR. 


Copyrighted  by  EDWARD  ALLISON  HILL 
February,  1922.     All  rights  reserved 


CHAPTER  I 

A  GLANCE  AT  EARLY  OIL  FIELDS  IN  CALIFOR- 
NIA AND  MENTION  OF  OTHER  REGIONS 

AS  LONG  ago  as  1896  it  appeared  probable  that  the 
State  would  develop  great  oil-producing  areas.  Dur- 
ing that  year  drilling  in  the  Coalinga  district  opened  a 
flowing  well.  The  known  productive  areas  in  the  southern  part 
of  the  State  which  had  shown  profitable  output  before  that  time 
were  a  considerable  distance  from  the  "Blue  Goose"  well  near 
Coalinga,  and  the  new  discovery  fanned  the  torch  of  activity 
into  a  blaze  of  excitement,  which  carried  new  drilling  like  a 
wave  of  heat  throughout  every  favorable  and  many  unfavor- 
able portions  of  California.  It  was  known  that  many  locali- 
ties appeared  geologically  similar  to  the  areas  in  which  oil  had 
been  found.  That  inference  led  to  the  formation  of  many 
exploitation  companies,  which  did  a  lot  of  drilling  throughout 
the  State. 


CALIFORNIA  AND  OTHER  FIELDS 


That  early  period  of  activity  brought  into  existence  many 
successful  companies;  some  new  fields  were  discovered  and 
the  known  fields  were  widened  and  extended.  Referring  to  the 
epoch,  a  publication  of  the  California  State  Mining  Bureau 
known  as  Bulletin  No.  32,  "Production  and  Use  of  Petroleum 
in  California,  page  1  1 ,  says : 

when  the  excitement  had  passed  away  the  pro- 
duction of  the  State  had  increased  from  two  and  one-half  mil- 
lion to  nearly  seven  and  three-quarter  million  barrels  per  annum, 
and  an  enormous  amount  of  well-invested  capital  remained  in 
the  business,  and  it  had  been  shown  that,  under  rational  man- 
agement, the  production  of  and  the  prospecting  for  petroleum 
in  California  formed  a  legitimate  employment  for  capital." 

Relative  to  the  results  that  followed  drilling,  a  table  of  field 
activities  tabulated  on  page  19  of  the  Bulletin  shows: 
"RECORD  OF  FIELD  OPERATIONS  TO 
DECEMBER  31,  1903 

"Producing  wells,  2998.  Abandoned  wells,  1271 .  Wells 
drilling,  1 59.  Wells  of  doubtful  value,  322."  The  record 
includes  a  total  of  4750  actual  drill  holes  put  down  in  the 
State  to  that  date,  of  which  2998  were  productive,  a  proportion 
of  successes  which  represents  better  than  60%,  without  taking 
account  of  any  part  of  the  322  holes  set  down  as  doubtful. 

The  record  of  petroleum  output  for  the  year  1919  will  give 
a  clear  idea  of  the  tremendous  growth  of  the  industry  during 
the  15-year  period  from  1903  to  1919.  Bulletin  No.  88, 
California  State  Mining  Bureau.  "California  Mineral  Produc- 
tion for  1919,"  page  23: 

"  .  .  .  sworn  statement  from  the  producers  of  8932 
wells  .  .  .  101,073,517  barrels  valued  at  $142,610,- 
563 — the  total  is  inclusive  of  some  small  output  of  the  Los 

10 


OIL  FIELD  STATISTICS 


Angeles  City  field."  (Page  24)  "from  the  Coalinga  field 
16,091,037  barrels  ...  the  average  daily  production 
from  California  wells  decreases  about  two  barrels  each  year. 
In  order  to  maintain  a  given  total  output,  new  wells  must  be 
continually  drilled."  (P.  26)  "The  total  production  of 
petroleum  since  the  date  of  discovery  in  1875,  inclusive  of  the 
production  for  1919,  is  recorded  as  1,240,198,740  bbls." 

The  actual  cash  value  of  this  enormous  production  of  one  of 
the  world's  most  vital  mineral  resources  has  not  been  far  from 
a  billion  dollars.  Again  it  may  be  repeated,  the  economic 
worth  of  that  great  addition  to  the  State's  vested  riches  is  almost 
beyond  possible  calculation. 

Bulletin  32,  page  1  7,  regarding  the  values  of  land  in  the 
various  fields,  reports:  "Land  values  run  from  $3,500  to 
$5,000  per  acre  in  the  better  parts  of  Kern  River;  from  $500 
to  $1,000  at  Sunset;  in  Midway,  as  high  as  $1,000;  at 
Coalinga,  from  $250  to  $4,000  or  $5,000.  At  Kern  it  is 
customary  to  allow  from  one  to  two  acres  for  each  well;  at 
Sunset,  about  the  same;  at  Coalinga,  from  one  to  four  acres." 

It  will  be  seen  that  the  identical  processes  were  operative  in 
California  which  had  theretofore  been  prevalent  in  all  oil  fields 
the  country  over.  Indeed,  the  results  of  discovering  oil  in 
profitable  commercial  quantities  in  any  new  locality  are  today 
parallel  in  every  respect  as  regards  vastly  enhanced  prices  of 
lands  and  leases.  The  striking  of  oil  almost  in  the  twinkling 
of  an  eye  sends  land  values  to  unbelievably  high  levels.  Such 
vast  increase  of  value  brought  about  in  so  short  a  period  of  time 
is^  the  underlying  cause  of  the  compelling  allurement  which 
urges  the  pioneer  to  never  weary  of  searching  for  new  pools  of 
oil.  It  is  the  magnet  which  attracts  capital  from  every  imagin- 
able source  to  assist  in  pioneer  drilling.  Were  it  not  for  the 

11 


OIL  MAKING  FORMATIONS 


tremendous  returns  which  flow  to  the  successful  operators  in 
new  regions  when  a  profitable  well  is  brought  in,  it  seems  likely 
that  what  is  known  as  wildcat  drilling  would  not  often  be  under- 
taken. It  is  that  kind  of  pioneering  work,  however,  which  has 
kept  the  United  States  in  the  lead  of  all  the  countries  of  the 
earth  in  petroleum  output.  It  is  the  character  of  venturing 
which  of  necessity  must  be  kept  up  if  the  petroleum  output  of 
the  country  is  to  equal  the  requirements  of  the  increased  and 
increasing  demands. 

Not  less  potent  were  the  Pennsylvania  formations  of  the  early 
Appalachian  fields  in  firmly  establishing  the  oil  production  of 
America  upon  a  solid  foundation,  than  are  formations  of  later 
periods  in  other  regions  effective  in  keeping  the  industry  upon 
such  basis.  The  Trenton  limestone  of  Ohio,  Indiana  and 
Illinois  has  done  and  is  doing  its  part  in  oil  output;  though  it  is 
a  formation  belonging  in  the  Ordovician  era,  deposited  during 
the  Silurian  period,  which  was  many  ages  before  the  Pennsyl- 
vania. The  great  fields  of  the  mid-western  States,  Kansas, 
Oklahoma  and  Texas,  the  most  profitable  regions  of  oil  output 
of  high  gravity  refining  quality  ever  drilled  in  any  country, 
deliver  their  values  from  the  Pennsylvania  formations.  The 
remarkable  fields  of  south  Texas,  known  as  the  Gulf  Coastal 
fields,  in  which  classification  Louisiana  largely  belongs,  release 
their  production  from  formations  of  the  Upper  Cretaceous  and 
Tertiary  periods;  and  it  is  in  the  Upper  Cretaceous  that  the 
notable  wells  of  the  Mexia,  Texas,  field  are  being  drilled. 
The  Colorado  shales  of  the  last  named  period  are  the  source 
of  the  Wyoming  and  Montana  petroleum  in  great  part. 

But  it  should  be  remembered  that  the  mere  presence  of  the 
organic  shales  of  the  thick  formations  of  the  periods  named  is 
not  within  itself  sufficient  to  an  area  to  guarantee  the  finding  of 

12 


oil  in  profitable  amount  by  drilling  at  random.  There  must 
exist  also  what  are  called  Oi7  Structures  to  render  practicable 
drilling  at  once  feasible  and  successful.  These  considerations 
will  be  discussed  in  later  sections  of  this  booklet,  and  it  will  be 
seen  that  they  apply  to  all  California  areas  with  equal  force  to 
their  application  in  other  oil-producing  regions,  though  the  shales 
of  the  State  are  among  the  richest  oil-bearing  formations  known. 


13 


CHAPTER  II 
THE  ORGANIC  SHALES  OF  CALIFORNIA 

IT  appears  to  have  been  quite  definitely  established  that  the 
probable  sources  of  the  petroleum  of  California  are  in  the 
organic  shales  deposited  during  Upper  Cretaceous  and  Ter- 
tiary periods,  though  some  higher  gravity  oils  of  amber  and  very 
light  greenish  color  are  thought  by  the  present  writer  to  come 
from  the  Ordovician — probably  Silurian  strata.  While  it  may 
be  set  down  as  being  likely  that  accumulations  of  the  last  men- 
tioned grades  of  oil  will  be  found  in  profitable  quantity  in 
properly  enclosed  catchment  reservoirs  in  certain  districts  in  and 
adjacent  to  Sacramento  Valley,  and  in  the  foothills  of  the  Coast 
Range  in  that  portion  of  the  State,  no  large  commercial  output 
of  the  peculiar  oil  described  has  yet  been  developed  in  the  re- 
gions named  or  elsewhere  in  California.  The  chief  output  of 
the  State  has  been  and  is  being  delivered  from  Tertiary  shales, 
though  millions  of  dollars  of  petroleum  values  have  been  and 
are  being  taken  from  strata  which  were  saturated  by  the  oil 
from  rich  shales  of  Upper  Cretaceous  epochs. 

14 


CALIFORNIA  PHYSIOGRAPHY 


Examination  of  a  topographic  map  of  the  State  will  be  of 
service  in  giving  a  good  idea  of  the  regions  where  organic  shales 
in  great  quantity  may  be  expected.  It  will  be  noted  that  the 
land  area  is  definitely  divided  into  two  major  physiographic 
features:  the  section  which  occupies  the  extensive  basin  area, 
and  the  sections  where  uplifted  strata  are  now  represented  by 
mountain  ranges.  The  former  was  covered  throughout  long 
geological  ages  by  the  waters  of  an  inland  sea  or  embayment, 
and  upon  its  floor  there  were  deposited  the  great  thicknesses  of 
shales  and  sands  now  found  to  be  oil  bearing.  That  old  sea 
was  somewhat  near  300  miles  long  north  and  south,  and  about 
50  miles  wide.  Upon  the  eastward  side  it  was  enclosed  by 
the  mountain  system  known  as  the  Sierra  Nevadas;  upon  the 
western  side  its  boundary  was  the  Coast  Range.  For  parts  of 
successive  ages  the  last  named  boundary  appears  to  have  been 
a  discontinuous  land  surface  made  up  of  the  summits  of  higher 
peaks,  forming  a  chain  of  islands.  Throughout  later  epochs 
more  or  less  extensive  earth  movements  closed  up  the  gaps 
between  the  islands  by  erogenic  (mountain-making)  and  tec- 
tonic (structural)  actions,  and  by  the  breaking  down  and 
erosion  of  the  existing  summits,  to  the  effectual  building  of  a 
coastal  mass  of  relatively  high  elevation. 

Though  it  should  not  be  overlooked  that  there  are  other 
areas  in  the  State  where  profitable  oil  output  comes  from 
organic  shales  which  are  not  an  integral  part  of  the  defined 
geological  province  described,  such  formations  are  known  to 
have  been  deposited  during  identical  epochs  and  under  condi- 
tions largely  parallel  with  conditions  obtaining  in  the  province 
of  the  great  embayment,  now  known  as  San  Joaquin  and 
Sacramento  Valleys. 


15 


It  will  be  seen  that  cut  No.  1  is  a  view  of  the  topography 
of  a  very  definitely  disclosed  anticline,  while  cut  No.  2  is  a 
diagram  of  the  topography  shown.  To  obtain  a  correct  idea 
of  the  underlying  strata  it  is  necessary  that  surface  exposures 
of  such  formations  be  present  in  the  region.  These  surface 
pictures  of  the  relative  position  of  the  formations  are  best  seen 
and  most  likely  to  be  found  in  the  localities  where  erosion  has 
carried  away  adjacent  and  overlying  strata,  leaving  the  edges 
of  the  deeper  formations  showing  in  the  side  of  creek  banks, 
cliffs  and  other  natural  excavations  and  elevations. 

As  pictured  in  cut  No.  2,  it  will  be  noted  that  the  formation 
marked  "Lower  Cretaceous,"  which  underlies  the  stratum 
marked  "Dakota  Sandstone,"  and  overlies  the  formation 
marked  "Morrison  Formation,"  is  determined  along  the  slope 
of  the  highest  elevation  of  the  landscape,  and  that  the  other 
formations  lying  with  it  are  depicted  in  their  relative  position. 
That  place  of  the  Lower  Cretaceous  member  would  be  main- 
tained underground  in  its  precise  relation  to  the  other  formations, 
and  could  be  so  mapped. 

If  there  were  conditions  present  which  would  contradict  the 
conclusion  stated  with  reference  to  the  relative  position  of  the 
formations  underground,  such  facts  would  be  plainly  marked 
in  some  manner  on  the  surface  and  could  be  taken  account  of 
in  the  investigation. 


17 


EARLY  PLANT  LIFE 


Within  the  shale  formations,  which  were  deposited  in  a 
horizontal  position,  as  all  other  sedimentary  formations  were 
deposited,  there  were  embedded  vast  quantities  of  marine  plant 
and  animal  organisms.  What  we  know  as  the  Diatomaceous 
earths  of  California  offer  examples  of  the  character  of  shales  in 
which  much  of  the  petroleum  of  the  State  had  origin.  Shales 
of  the  late  Upper  Cretaceous  are  also  of  similar  organic  char- 
acter and  provide  a  substantial  portion  of  the  oil  production 
which  has  placed  California  in  the  lead  of  petroleum-producing 
States. 

In  the  comparatively  shallow,  warm  waters  mentioned,  tre- 
mendous growths  of  algae,  fungi,  lycopods,  equisetas,  filices 
and  other  forms  of  early  plant  life  falling  within  the  kingdom 
known  as  Cryptogams,  choked  the  sea  and  clothed  the  waters 
throughout  vast  epochs.  As  these  plants  spread  and  multiplied 
and  flourished,  and  as  their  decaying  portions  sunk  to  the  bot- 
tom with  the  myriads  of  minute  animal  organisms  which 
swarmed  about  and  clung  to  their  tendrils,  the  ooze  and  slime 
on  the  sea-floor  gathered  inch  by  inch,  foot  by  foot,  into  hun- 
dreds and  thousands  of  feet  in  thickness ;  for  their  numbers  were 
almost  infinite,  their  aggregate  quantity  almost  beyond  imagina- 
tion, and  the  factor  of  time  was  so  long  that  the  mind  fails  to 
comprehend  and  the  fancy  halts  before  picturing  its  immensity. 
If  we  omit  a  tabular  summary  of  the  plant  and  animal  life  of 
the  Paleozoic,  which  ended  with  the  beginning  of  the  Mesozoic 
era,  and  which  tabulation  and  descriptions  make  up  an  extensive 
literature,  and  mention  only  the  fact  that  the  latter  era  passed 
with  the  beginning  of  the  Cenozoic,  and  state  that  the  remains 
of  its  plant  and  animal  life  provided  organic  sediments  in  quan- 
tities entirely  beyond  our  imagination,  we  have  not  even  then 
entered  the  maze  of  life  which  existed  in  the  last  named  era, 

18 


PETROLEUM  MAKING  PROCESS 


in  which  is  included  the  Tertiary  period.  Nor  should  it  be 
thought  that  the  varied  forms  of  life  were  less  numerous,  or 
that  the  multitude  of  individuals  of  the  countless  species  was 
not  so  great,  or  that  the  vast  stretch  of  time  was  more  shortened 
for  the  later  than  for  the  earlier  epochs.  The  stupendous  total 
of  organic  creatures,  animals  and  plants  of  land  and  sea,  the 
embedded  remains  of  vestiges  of  which  are  preserved  to  our 
examination  in  the  shales  of  the  Upper  Cretaceous  epoch  and 
the  Tertiary  period,  we  may  understand  were  quite  abundant 
in  quantity  for  the  provision  of  the  antecedents  for  the  natural 
making  of  more  petroleum  than  oil  drillers  have  yet  had  time 
to  find. 

So,  this  section  ends  as  it  started  with  the  statement  that  the 
organic  shales  appear  to  have  been  sufficiently  determined  as 
the  source  of  California  petroleum.  Since  scientists  have  quite 
fully  achieved  in  laboratory  experimentation  a  copy  of  natural 
processes  in  the  genesis  of  petroleum,  it  transpires  that  much  is 
accurately  known  about  what  methods  were  followed  by  Nature 
in  making  the  oil  we  find  in  the  ground.  The  learned  chem- 
ists of  the  world  engaged  in  such  studies  compound  a  meager 
quantity  of  ingredients  and  generate  an  ounce  or  more  of  petro- 
leum therefrom  within  a  few  hours  or  a  few  days,  while  Nature 
used  the  forces  and  exhaustless  ingredients  of  a  world  as  a 
laboratory  in  which  to  generate  billions  of  barrels  of  petroleum 
during  multiplied  millions  of  years  of  working  time ;  and  in  each 
case  similar  ingredients,  like  forces  and  parallel  methods  are 
called  into  use.  Hence,  it  occurs  now  that  the  origin  of  petro- 
leum is  in  a  manner  quite  well  known,  to  an  appreciable  extent 
what  conditions  surround  its  making,  and  in  a  more  or  less 
definite  way  the  methods  and  laws  involved  in  the  process.  It 
is  largely  because  of  that  knowledge  that  we  understand  rea- 

19 


OIL  MAKING  PROCESS 


sonably  well  in  what  formations  to  expect  it,  and  have  acquired 
information  about  how  to  locate  such  formations,  estimate  their 
probable  petroleum  content  and  decide  whether  possible  accum- 
ulation reservoirs  have  been  provided  by  earth  movement  for  the 
gathering  and  impounding  of  the  petroleum  in  such  formations 
or  in  contact  beds. 

The  foregoing  considerations  have  carried  us  to  the  point  of 
directing  some  attention  to  the  interesting  methods  employed  in 
determining  the  age  of  various  formations,  learning  under  what 
conditions  the  sedimentation  took  place  and  what  possible 
economic  value  such  knowledge  may  embody. 


20 


CHAPTER  III 

REMARKS   ABOUT    IDENTIFICATION    OF    DE- 
POSITS AND  DETERMINATION  OF  AGE, 
AND  THE  USE  OF  THAT  KNOWLEDGE 

THE  profound  study  which  has  been  given  to  every 
variety  of  rock  formations  throughout  the  world  over 
a  long  period  of  time  by  men  of  such  learning  that  we 
delight  to  honor  them  has  extended  our  fund  of  knowledge  to 
a  point  of  actual  certainty  with  respect  to  nearly  all  rocks.  It 
should  be  said  that  geologists  call  all  formations  "rocks'* ;  even 
the  dirt  in  the  streets  and  the  soil  in  the  fields  are  known  to 
scientists  as  rocks.  It  was  said  that  nearly  all  rocks  are  known 
which  is  intended  to  mean  that  it  is  known  somewhat  definitely 
what  constitutes  their  material  and  when  they  were  deposited 
in  the  time  scale,  as  related  to  other  deposits. 

The  remains  of  minute  insects,  equally  with  those  of  the 
largest  serpents  and  biggest  creatures  of  every  kind,  such  as 
lived  upon  the  land  and  in  the  waters;  the  stems  and  leaves  of 
plants,  marine  and  terrestrial  alike;  the  shells  and  skeletons  of 
every  kind  of  land  and  water  infesting  thing  of  life,  would  most 

21 


IDENTIFYING  FORMATIONS 


naturally  be  embedded  in  some  quantity  in  the  formations  which 
were  constantly  being  put  down  throughout  every  past  age  under 
bodies  of  water  everywhere.  As  time  passed,  some  of  these 
formations  would  be  exposed  at  some  place  upon  the  surface; 
indeed,  every  one  of  them  would  be  uncovered  somewhere  upon 
the  earth,  some  at  one  place,  others  somewhere  else,  many  of 
them  again  at  another  place;  until  here  and  there  in  almost 
countless  localities  there  would  appear  every  sedimentary  deposit 
ever  put  down.  Embedded  in  them  would  be  the  impressions, 
moulds,  casts,  or  rock-encrusted  or  fossilized  remains  of  the 
varied  and  various  species  of  plant  and  animal  life  which  had 
during  any  period  grown  in  the  earth  or  the  oceans,  crawled 
upon  the  dry  land,  flown  through  the  air,  or  swarmed  in  the 
water  of  the  seas.  Such  fossils  have  enabled  many  of  the 
world's  most  learned  men,  working  and  studying  in  every  coun- 
try upon  the  earth,  to  classify  and  distinguish  the  species  and 
individuals  of  one  age  from  like  and  unlike  species,  and  in- 
dividuals of  another.  It  has  been  found  that  the  plants  and 
animals  of  any  given  epoch  during  the  vast  stretch  of  time  that 
has  silently  passed  in  almost  infinite  measure  down  through  the 
dim  corridors  of  the  ages,  have  maintained  that  character  of 
progression  and  so  fit  into  the  mosaic  of  evolving  forms,  as 
adapts  them  to  methods  of  intelligible  interpretation. 

The  beautiful  shells  and  other  fossils  often  seen  in  rocks  are 
the  actual  records  left  along  the  shores  of  time  as  an  ineffaceable 
literature  of  the  plants  and  animals  of  past  ages.  If  one  gave 
a  lifetime  to  the  study  of  these  records  and  to  comparison  of 
them  as  to  similarities  and  differences,  and  extend  the  search  to 
all  lands  upon  the  earth,  studying  them  in  canyons,  gorges, 
cliffs,  shores  and  mountainsides,  and  carry  with  him  specimens 
of  every  varying  kind  he  finds,  he  will  be  surprised  and  de- 

22 


CLASSIFYING  LIFE  FORMS 


lighted  in  the  end  to  see  how  many  of  them  will  be  similar  in, 
some  main  essential,  how  many  will  be  alike  in  some  other  par- 
ticular, and  how  many  will  be  wholly  unlike  in  almost  every 
respect.  Also,  he  will  be  amazed  to  learn  at  last  into  how 
many  classes  he  shall  be  compelled  to  divide  them,  and  how  few 
individual  specimens  there  will  actually  remain  in  each  class. 
The  investigations  mentioned  have  been  pursued  for  many  years 
throughout  all  parts  of  the  world  by  thousands  of  learned  men 
in  a  most  earnest  manner,  and  the  results  have  been  set  down 
in  careful  descriptions  and  photographs,  so  that  the  vast  amount 
of  accurate  knowledge  gathered  is  open  to  the  study  of  every 
one.  A  great  architect  might  not  have  the  time  or  means  to 
visit  every  country  on  earth  and  examine  the  form  of  every  style 
of  architecture,  but  with  photographs  and  exact  specifications 
of  every  character  of  building  before  him,  he  would  not  mistake 
one  style  for  another.  That  is  true  of  the  geologist  regarding 
different  formations;  he  must  know  if  the  exposed  strata  upon 
one  side  of  a  hill  is  a  part  of  the  identical  strata  exposed  on 
another  slope.  Information  of  formations  must  be  so  full  that 
two  elevations  taken  upon  what  is  thought  to  be  the  same  for- 
mation in  nearby  areas  will  not  in  fact  be  the  levels  of  different 
deposits  put  down  during  epochs  separated  by  a  time  interval 
of  possibly  millions  of  years.  Indeed,  the  Molluscoid  forms 
or  any  other  forms  of  the  animal  kingdom  of  the  Cambrian 
period  must  not  be  confounded  with  the  descendants  of  such 
marine  creatures  of  the  Permian  period — separated  in  the  time 
sc/ile  and  rock  stage  by  many  millions  of  years.  Such  confu- 
sion would  render  futile  the  results  of  an  examination  of  any 
region,  and  perilous  indeed  would  be  the  employment  of  funds 
based  upon  such  inaccurate  conclusions;  yet  the  writer  has  re- 
ported upon  many  locations  of  drilling  wells  where  it  was 

23 


SOURCES  OF  PETROLEUM 


apparent  mistakes  of  equally  glaring  character  had  been  made, 
though  not  by  an  authority  who  could  scientifically  determine 
where  a  drill  should  be  located. 

During  Upper  Cretaceous  times,  not  to  search  into  deeper 
past  epochs  than  such  as  are  suitable  to  the  illustration,  it  has 
been  found  that  certain  species  of  very  minute  marine  plants, 
known  as  algae,  were  similar  in  the  waters  of  equable  tempera- 
ture in  every  sea  of  the  world.  Such  plant  life  and  others  of 
similar  and  unlike  character,  together  with  the  diminutive  animal 
life  of  the  seas,  have  been  found  to  be  the  source  of  much  of  the 
petroleum  coming  from  formations  of  that  age.  The  fossils 
preserved  in  the  strata  render  them  not  difficult  of  determination. 

Later,  during  the  Tertiary  period,  there  seems  to  have  been  a 
marked  development  and  increase  of  one  branch  of  algae,  known 
as  diatoms,  so  that  their  growth  filled  the  waters  which  sub- 
merged a  part  of  what  is  now  the  great  valley  area  of  Califor- 
nia. Our  diatomaceous  shales  are  so  named  because  the  greater 
proportionate  part  of  such  shales  are  often  almost  entirely  com- 
posed of  the  limey  portion  of  that  marine  plant. 

Since  other  forms  of  plant  and  animal  life  were  embedded  in 
the  shales  and  other  formations  of  the  periods  named,  it  be- 
comes apparent  that  there  is  no  uncertainty  as  to  what  relative 
time  must  be  referred  these  minute  specimens  of  organic  life. 

The  accuracy  to  which  age  correlation  and  identification  of 
strata  have  been  carried  by  science  will  bear  one  full  illustra- 
tion: It  is  possible  to  trace  with  unerring  assurance  the  physical 
history  of  the  horse  from  his  embedded  remains  in  formations 
of  the  Eocene  epoch  of  the  Tertiary  period  to  the  present  time. 
Similar  methods  are  employed  in  the  identification  of  the  devel- 
oping and  changing  forms  of  every  species  of  plant  and  animal 
life,  as  such  alterations  were  brought  about  by  the  adaptations 

24 


THE  PASSING  OF  SPECIES 


enforced  by  survival.  But  it  is  especially  interesting  to  follow 
the  skeletons  of  the  horse  backward  from  his  present  proud  and 
beautiful  form  into  the  inhospitable  conditions  of  the  early  Ter- 
tiary, a  long  period  of  volcanic  eruptions,  and  of  widespread 
and  almost  continuous  earth  movements.  The  atmosphere  was 
laden  with  noxious  gases,  the  waters  contained  acids,  were 
saline,  sulphurous  and  choked  with  ashes  and  volcanic  dust; 
and  when  such  perplexities  were  joined  to  the  perils  of  a  quak- 
ing earth,  avalanches,  lava  flows,  the  opening  of  extensive  fis- 
sures where  the  solid  strata  were  broken  and  uplifted  by  faulting, 
buckling  and  folding,  combining  to  the  enforcement  of  constant 
and  rapid  shifting  of  places  of  habitat,  it  is  indeed  marvelous 
that  the  creature  survived  not  only,  but  with  the  multiplying 
stages  of  growth  and  improvement  became  the  fleet  and  comely 
animal  of  our  prize  shows.  Not  less  strange  is  it  that  of  all 
the  animal  and  plant  life  which  has  ever  inhabited  and  clothed 
the  planet,  the  myriad  wonderful  representatives  which  have  de- 
scended into  our  day  are  but  a  scant  fraction.  The  vast  pano- 
rama of  life  which  has  in  every  age  been  spread  out  over  the 
lands  and  in  the  seas  has  in  every  species  changed,  some  falling 
backward  and  dying  out,  others  improving  and  multiplying ;  but 
we  know  that  all  were  of  Nature  and  exist  within  the  horizon 
of  Divine  provision.  In  that  ancient  system  of  rocks  where  the 
earliest  remains  of  the  horse  have  been  preserved  in  skeletons 
which  do  not  change,  we  learn  that  he  was  about  the  size  of  the 
fox  squirrels  of  today.  In  the  formations  of  every  succeeding 
eppch  from  the  first  remains  found  there  have  been  unearthed 
and  identified  hundreds  of  skeletons  which  are  unmistakably  the 
remains  of  horses.  The  writer  has  examined  parts  of  skeletons 
of  horses  of  the  Pleistocene  epoch  embedded  in  formations  of 
that  sedimentation  in  Florida.  In  Wyoming  he  has  seen  the 

25 


GEOLOGY  AND  PALEONTOLOGY 


bones  of  such  skeletons  embedded  in  rocks  of  the  early  Miocene 
epoch.  There  may  be  seen  in  museums  many  almost  wholly 
complete  skeletons  of  the  horse  of  every  epoch  from  the  first 
identifiable  structures  of  his  beginning  to  the  present  time.  It 
will  be  remembered  that  the  character  of  the  herbiage  changed 
as  epoch  grew  into  epoch  with  the  passing  of  ages,  and  that  as 
age  followed  age  grasses  came  and  flourished  and  developed, 
and  that  climatic  and  atmospheric  conditions  evolved  environ- 
ments and  influences  which  provided  better  food  and  more 
favorable  surroundings,  hence  the  animal's  additions  of  size  and 
strength. 

In  the  formations  filling  some  of  the  hollows  of  such  old 
bones,  where  marrow  had  been  in  the  living  animal,  there  have 
often  been  found  many  bony  structures  of  insects  and  other 
animal  organisms,  impressions  of  plant  leaves  and  stems  and 
other  remains  of  the  living  things  of  the  earth  belonging  to  the 
particular  epoch  of  the  bones  when  a  part  of  the  living  animal. 
Hence,  we  come  to  the  knowledge  of  many  verifying  and  cor- 
roborative facts  relative  to  the  contemporary  life  and  many  of 
the  happenings  of  every  epoch. 

The  science  of  rocks  is  called  Geology.  The  science  of  fos- 
sils is  called  Paleontology.  These  sciences  are  as  essential  to 
the  successful  oil  driller  as  the  science  of  chemistry  is  necessary 
to  the  steel  manufacturer.  The  major  oil-producing  companies 
and  all  successful  oil  operators  employ  men  learned  and  experi- 
enced in  these  professions  to  examine  possible  oil-bearing  lands 
and  select  locations  for  drilling,  as  the  steel  maker  employs 
chemists  to  advise  proper  alloys  in  right  quantities  for  the  mixing 
and  fusing  of  iron  ores  in  the  blast  furnace.  The  railway 
companies  and  others  demand  steel  of  a  specified  chemical 
composition,  hence  the  steel  maker  must  employ  scientific 

26 


SCIENTIFIC  KNOWLEDGE  NECESSARY 


advisers  of  learning  and  experience  in  order  to  deliver  such 
grades. 

The  oil  producer  is  very  rarely  a  competent,  experienced 
scientist,  but  if  he  wishes  to  locate  new  fields  he  employs  capable 
geologists  to  that  end.  The  steel  manufacturer  is  rarely  if  ever 
a  learned  and  experienced  chemist,  but  he  is  not  without  the 
advice  of  men  learned  and  experienced  in  that  profession. 


27 


28 


In  cut  No.  3  a  dome  is  shown.  The  hills  of  light-colored 
material  in  the  central  part  of  the  picture  are  made  up  of  rocks 
of  much  greater  age  than  the  formations  in  the  crests  of  the 
ridges  lying  about  them.  If  by  reason  of  vertical  action  there 
is  a  body  of  formations  pushed  upward  in  a  local  area,  it  will 
be  obvious  that  such  formations  as  lie  over  that  body  will  be 
elevated,  and  by  that  movement  will  upturn  the  edges  of  the 
strata  which  were  broken  by  the  upthrust. 

It  usually  develops  that  in  cases  like  the  foregoing  the  domal 
part  of  the  structure,  the  top  of  the  dome,  is  subject  to  greater 
erosional  activities  than  the  surrounding  material.  It  also 
follows  that  the  disintegrated  mass  of  formations  which  most 
definitely  express  the  character  of  the  action  are  the  ends  and 
edges  of  strata  which  were  lying  more  deeply  buried,  hence 
are  more  compact,  denser  and  harder  than  the  formations  pushed 
up  in  the  central  portion  of  the  dome;  therefore  their  upturned 
portions  do  not  erode  away  so  rapidly.  The  top  of  the  dome 
carries  greater  or  less  thicknesses  of  the  material  which  was  upon 
and  near  the  surface,  hence  surrenders  more  readily  to  the  ele- 
ments, leaving  a  depression  wherein  there  is  left  upon  the  sur- 
face the  hard  formations  which  belong  to  rock  stages  much 
earlier  than  the  surrounding  rim  of  rocks  which  bound  the 
dome. 

For  the  reason  stated,  though  other  causes  also  enter  into 
the  fact,  domes  and  anticlines  will  often  express  their  highest 
understructure  along  creek  and  river  beds  and  sometimes  in 
lakes.  Much  of  the  Cherokee  Shallow  Oil  Fields  of  Okla- 
homa are  illustrative  of  the  first;  and  Caddo  Lake,  Louisiana, 
of  the  latter. 


29 


CHAPTER  IV 

RELATING  TO  OIL  STRUCTURES  AND  THE 
METHODS  OF  DETERMINING  THEM 

The  dependable  results  gained  by  drilling  experience 
throughout  the  world  have  established  a  vast  assembly  of  facts 
relative  to  oil-bearing  formations,  and  the  laws  and  conditions 
which  govern  oil  accumulation  in  certain  areas. 

The  fact  will  not  be  lost  sight  of  that  there  are  certain  im- 
perative essentials  which  are  antecedent  to  the  discovery  of  new 
oil  fields.  Though  it  would  be  manifestly  impossible  to  stay 
within  the  boundaries  of  a  brief  plan  if  we  enter  fully  into 
discussion  of  the  almost  countless  minor  details  and  aspects  of 
the  less  important  conditions  which  must  be  considered  by  the 
geologist  in  locating  a  new  field,  it  is  possible  to  set  down  in  a 
few  short  paragraphs  the  main  factors  which  are  of  first 
moment. 

30 


LAWS  OF  OIL  STRUCTURES 


1.  The  presence  of  petroleum-making  formations  must  be 
known  to  exist  in  the  sub-surface  strata  either  directly  or  in 
contact  in  the  inclined  beds. 

2.  Permeable  formations,  such  as  sand,  porous  limestone, 
or  other  sediments  in  which  oil  could  find  lodgment,  must  be 
accessible  to  the  oil-making  formations. 

3.  The  oil-making  strata  and  the  formations  acting  as  a 
reservoir  into  which  the  oil  has  passed  must  occupy  such  rela- 
tive positions  as  provide  or  have  provided  for  the  oil  to  move 
from  the  former  into  the  latter. 

4.  The  permeable  formation  in  which   the  oil   has   had 
natural  provision  for  accumulation  must  be  enclosed  by  imper- 
meable strata,  or  otherwise  be  definitely  surrounded  by  rock 
formations,  so  that  the  oil  draining  into  it  could  not  have  been 
lost  by  escape  to  the  surface. 

The  foregoing  conditions  are  interpreted  as  oil  structures, 
such  as  the  Anticline,  Dome,  etc.,  etc.,  of  which  there  will  be 
something  said  later.  Disregard  or  ignorance  of  the  absence 
of  facts  similar  to  such  as  are  mentioned  above  has  been  re- 
sponsible for  the  drilling  of  a  very  large  number  of  holes  in 
attempts  to  find  oil  in  regions  and  at  locations  where  no  effort 
of  the  character  should  ever  have  been  made.  The  shales 
from  which  oil  is  generated  and  the  limestones  from  which  it  is 
distilled  by  natural  processes  are  fairly  well  known  throughout 
all  of  the  oil-producing  regions  of  the  world.  Also,  the  various 
kinds  of  oil  structures  which  may  be  expected  to  contain  oil 
accumulations,  if  present  in  a  region  where  oil-bearing  forma- 
tions are  believed  to  occupy  sub-surface  levels,  are  not  usually 
difficult  of  discovery  and  location. 

There  are  areas  adjacent  to  nearly  all  productive  oil  fields 
which  contain  the  shales  and  limestones  in  which  the  oil  is 

31 


LOCATING  OIL  AREAS 


found  in  the  nearby  producing  area,  though  such  formations 
may  not  lie  in  a  favorable  position  or  be  of  adequate  thickness 
to  warrant  drilling.  Often  because  of  some  other  ascertainable 
reason  oil  should  not  be  expected  in  them,  such  as  lack  of  poros- 
ity in  the  oil-bearing  members,  the  presence  of  water  because 
of  low  sub-surface  elevation,  or  some  prime  essential  which  is 
found  to  be  lacking — there  must  be  nothing  of  direct  bearing 
on  possible  oil  presence  absent  in  any  area  where  drilling  is 
to  be  done. 

In  a  great  many  areas  throughout  the  large  number  of  oil- 
producing  regions  of  the  United  States,  and  the  same  facts  are 
found  to  exist  in  fields  elsewhere  in  the  world,  it  has  been  noted 
that  new  fields  have  been  opened  in  nearby  or  related  areas 
after  the  development  near  the  discovery  well  had  progressed 
to  the  drilling  of  every  feasible  location  in  the  producing  field. 
It  is  often  possible  to  follow  the  oil-producing  and  oil-bearing 
formations  from  the  producing  districts  into  related  areas  either 
near  to  or  more  distantly  removed  from  present  production.  In 
event  we  are  able  to  trace  from  a  productive  area  into  a  nearby 
region  the  upturned  edges  of  alternating  sandstone  and  shale 
members  which  quite  definitely  express  the  conditions  of  such 
strata  as  to  sequence  of  deposit,  character  and  position  occupied 
under  the  new  region,  we  are  enabled  without  much  doubt  to 
reckon  upon  the  presence  of  oil  in  profitable  amount  in  any 
structure  found  in  the  latter  region. 

The  great  fields  which  came  at  last  to  show  almost  a  con- 
tinuous succession  of  profitable  wells  from  Robinson  to  Casey, 
Illinois,  is  a  case  in  point.  An  untested  area  in  that  region, 
known  to  the  writer,  may  be  another  case.  Also,  the  trend  of 
productive  strata  from  Caney,  Kansas,  to  Chelsea,  Oklahoma, 
in  the  great  Mid-Continent  fields,  a  distance  of  upward  of 

32 


LOCATING  OIL  AREAS 


seventy  miles,  was  traced  out  very  well  by  geologists  following 
the  exposures  of  formations  along  the  bases  of  the  hills  and  in 
the  cut-out  channel  of  Verdigris  River  upon  the  western  bound- 
ary of  the  region.  The  California  fields  located  in  southern 
San  Joaquin  Valley  and  at  Coalinga  offer  marginal  boundaries 
along  the  foothills  of  the  Sierras  and  the  Coast  Range  which 
are  almost  ideal  for  the  tracing  out  of  the  possible  oil-making 
and  oil-bearing  strata,  as  the  upturned  edges  of  these  are  ex- 
posed with  their  related  members  along  the  foothills  mentioned. 


33 


CHAPTER  V 

SOME  TYPES  OF  OIL  STRUCTURES  AND  RE- 
MARKS ABOUT  THEIR  CHARACTER  IN 
SOME  WELL-KNOWN  FIELDS 

THOUGH  all  formations  of  a  sedimentary  character 
were  deposited  in  a  horizontal  position,  but  rarely  are 
they  now  found  lying  in  that  position  in  any  region  of 
considerable   areal   extent.      The   crust   of    the   earth,    though 
stable  enough  in  the  present  epoch,  has  been  subject  to  almost 
endless  disturbances,  which  have  had  the  effect  of  displacing 
the  strata,  and  tilting,  upending,  breaking  and  rearranging  the 
sequence  of  rock  formations. 

The  planet  we  live  upon  has  gradually  contracted  in  size, 
causing  rock  strata  which  were  deposited  long  ago  to  lie  exposed 
upon  the  surface,  or  to  thrust  out  their  edges  where  erosion  has 
carried  away  the  disintegrated  and  loosened  material.  Many 
great  mountain  chains,  peaks  and  summits,  and  many  hills  and 
ridges,  with  their  related  or  corresponding  depressions  of  valley, 
plain,  gorge  and  canyon,  are  displayed  all  over  the  world  as 
results  of  the  buckling,  warping,  faulting  and  other  earth  move- 
ments occasioned  largely  by  that  contraction.  Of  course  the 
shrinkage  of  the  planet  has  been  entirely  too  slight  to  be  meas- 

34 


OIL  ACCUMULATION  FACTS 


ured  by  any  instruments  of  even  the  most  delicate  exactitude, 
but  the  inequalities  of  the  surface  of  the  earth  everywhere  bear 
legible  records  of  the  fact.  These  erogenic  and  tectonic  move- 
ments, mountain-making  and  structural,  respectively,  have  been 
taking  place  in  the  more  or  less  solid  crust  of  the  earth  through- 
out much  the  greater  part  of  its  physical  history,  though  very 
surely  quite  more  prevalent  in  some  ages  than  in  others.  They 
have  occurred  with  diminished  frequency  during  the  period  in 
which  men  have  lived  than  at  any  previous  time,  and  it  seems 
that  our  habitation  is  growing  more  nearly  secure  and  is  not  so 
much  beset  by  disturbances  as  period  is  added  to  period  in 
its  age. 

Such  movements  have  been  of  determining  effect  in  the  dis- 
placements which  have  provided  the  natural  rock  structures 
which  appear  to  exist  in  all  areas  where  oil  in  commercially 
profitable  amount  has  been  found.  There  are  several  well- 
known  types  of  these  so-called  oil  structures,  though  the  anti- 
cline and  dome  are  the  most  common  and  appear  to  be  the  types 
present  in  many  of  the  areas  of  greatest  productivity.  The 
various  forms  of  structure  have  been  so  definitely  determined  by 
drilling  in  hundreds  of  areas  in  all  oil-producing  regions  through- 
out the  world,  and  scientific  measurements  and  mapping  of  the 
surface  demarcations  of  such  structures  have  been  carried  to 
such  a  high  degree  of  accuracy,  that  it  appears  there  has  been 
established  a  series  of  related  natural  laws  regarding  the  gath- 
ering of  petroleum  into  catchment  reservoirs.  This  will  not  be 
understood  that  the  oil  is  contained  in  basins  in  the  ground  like 
pools,  lakes  or  rivers  upon  the  surface,  but  in  sand  and  other 
porous  formations,  as  water  is  contained  in  gravel. 

It  has  been  said  that  if  the  oil  found  in  any  great  oil  structure 
were  disseminated  back  into  the  formations  from  which  it 

35 


TYPES  OF  OIL  STRUCTURES 


drained  it  would  be  impossible  to  drill  a  profitable  oil  well  at 
any  location  upon  the  earth.  This  reflection  brings  us  to  a  more 
detailed  examination  of  what  is  meant  by  an  Oil  Structure,  and 
what  we  must  search  for  in  order  to  locate  that  peculiar  em- 
placement of  the  rock  strata. 

The  most  commonly  known  types  of  oil  structures  are  named 
after  the  specific  architectural  build  of  the  formations,  as  the 
anticlinal,  meaning  roof-like;  the  domal,  like  a  dome;  the 
terrace,  a  level  area  of  the  formations  interrupting  or  ending  a 
dip  plane;  etc.,  etc. 

ANTICLINE  OR  ANTICLINAL  FOLD:  This  type  of  structure 
is  more  common  than  any  other.  It  is  that  displacement  of  the 
strata  which  forms  an  arch  of  the  formations,  and  disposes  dips 
upon  two  opposing  sides  from  an  extended  apex.  The  inclined 
beds  are  in  the  place  of  the  sides  of  a  roof  over  a  building  and 
the  apex  is  in  the  position  of  the  ridge-pole. 

In  the  section  where  earth  disturbances  were  mentioned  it 
was  said  that  mountains,  hills,  valleys  and  other  inequalities  of 
the  earth's  surface  were  apparent  everywhere.  Referring  to 
such  elevations  and  depressions,  of  course  it  will  be  seen  that  if 
an  upward  movement  developed  from  the  buckling,  folding  or 
warping  of  underlying  formations,  there  would  be  a  more  or  less 
definite  elevation  of  all  overlying  strata.  Such  condition  would 
be  called  anticlinal,  and  would  be  inclusive  as  to  the  alternating 
formations  and  their  arching  similar  to  a  layer  cake  bent  upward 
across  the  middle — every  layer  would  bend  equally.  (See 
Cuts  1  and  2,  page  1 6. 

It  will  be  remembered  that  the  formations  were  put  down  in 
a  more  or  less  regular  position  horizontally  under  water.  They 
are  not  all  sand,  or  all  clay,  or  shale,  or  limestone,  or  of  any 
one  sedimentary  material.  In  drilling  wells  for  oil,  sinking 

36 


33 


The  character  of  the  topography  shown  in  cut  No.  4  is  not 
unlike  that  of  Devil's  Den  and  the  general  region  of  that  oil 
field  in  California.  It  requires  no  technical  examination  to 
determine  that  the  light-colored  sandstone  ledge,  shown  in  the 
left-center  foreground  in  the  cut,  passes  under  the  rocks  which 
define  the  escarpment,  shown  upon  the  right  and  middle  back- 
ground of  the  picture. 

However,  it  does  require  a  very  critical  examination  and  the 
exercise  of  constructive  logic  in  reasoning  from  the  facts  to 
determine  positively  if  there  be  an  unconformity  between  the 
former  and  the  latter,  and  if  a  catchment  area  for  oil  accumu- 
lation in  the  former  material  might  have  been  provided  by  the 
overlapping  upper  formation. 

The  picture  in  fact  sets  out  graphically  one-half  of  a  domal 
structure,  which  in  this  case  is  a  sealed  fault.  The  facts  deter- 
mined by  drilling  disclosed  an  upthrust  of  the  strata  shown  in 
the  picture,  leaving  the  formations  in  place  towards  the  left, 
though  not  shown.  The  test  well  was  located  in  this  instance 
about  five-eighths  of  a  mile  from  the  breakage  line  of  the  fault, 
just  back  of  the  highest  terrace  in  the  extreme  right-hand  side  of 
the  cut.  Oil  in  good  commercial  quantity  was  found  in  the 
lighfr-colored  sandstone  at  a  depth  of  1800  feet,  though  there 
were  some  little  seepages  of  it  along  the  sandstone  wall  shown 
with  the  trees  of  evergreen  variety  near  the  center  of  the  picture. 


39 


DEFINING  OIL  STRUCTURES 


shafts  for  mining,  or  digging  wells  for  our  domestic  water  sup- 
ply, we  see  that  there  is  usually  on  top  a  given  thickness  of  shale 
(shale  was  mud  at  first),  then  possibly  clay,  afterward  lime- 
stone and  then  sand  or  gravel.  The  succession  of  these  and 
other  formations  known  in  the  ground  vary  with  every  locality; 
almost  no  two  sections  of  any  depth  will  be  identical.  Any 
elevation  of  the  successive  strata  will  of  course  lift  all  of  them, 
and  in  most  cases  it  will  be  found  that  upon  one  side  or  the  other 
of  the  apex  of  an  arched  or  folded  area  there  will  be  a  longer 
slope  than  upon  the  other  side;  and  in  one  of  the  two  sides 
(limbs  of  the  anticline,  as  they  are  called)  there  will  be  a  steeper 
dip  than  in  the  other.  Also,  in  many  such  types  it  will  be  seen 
that  the  inclination  of  the  beds  as  they  dip  away  from  the  apex 
maintains  about  the  same  degree  of  pitch  and  will  extend  to  a 
distance  of  several  miles  upon  one  limb  of  the  anticline,  but  will 
be  dipping  at  a  very  steep  angle  upon  the  other  limb;  the  effect 
being  that  of  a  very  long  roof  on  one  side  and  a  very  short, 
steep  one  on  the  other.  The  direction  from  which  we  will 
expect  the  oil  to  have  migrated  into  the  anticline  will  usually 
be  from  the  long  side  of  the  roof,  and  in  making  a  location  for 
the  drilling  of  the  test  well  upon  the  structure  we  will  select  a 
site  near  the  apex  but  somewhat  upon  the  side  of  the  less  steeply 
dipping  beds.  There  are  local  conditions  present  sometimes 
which  would  vary  that  logic,  but  they  are  the  exceptions. 
Sometimes  the  anticline  will  be  very  regular,  the  limbs  upon 
either  side  of  approximately  uniform  inclination,  and  the  apex 
maintain  a  more  or  less  equal  elevation.  The  selection  of  a 
location  for  test  drilling  will  in  such  cases  be  approximately 
upon  the  apex.  It  will  often  be  seen  that  the  fold  did  not  pass 
through  the  area  in  a  straight  line ;  indeed,  such  uniform  straight 
folding  is  not  common.  The  apex  will  be  sinuous,  or  curved, 

40 


DESCRIPTION  OF  STRUCTURES 


or  present  a  turn  or  various  turns  at  sharp  or  more  rounded 
angles  in  nearly  all  areas  where  folding  has  developed  in  very 
thick  limestones  which  occupy  the  sub-surface  levels  throughout 
an  extensive  region,  or  in  a  region  of  prominent  folding  which 
results  from  vertical  thrusts  of  deeper  lying  massive  formations 
or  igneous  material. 

In  many  regions  where  the  folding  has  been  pronounced,  and 
the  action  has  been  in  great  measure  common  to  a  considerable 
area,  the  other  types  of  structure  will  also  be  very  likely  found. 
Domes  will  exist,  or  Terraces,  or  Faultings  or  Faulted  Zones, 
though  any  of  the  last  named  may  be  present  in  an  area  and 
no  other  form  of  structure  be  near. 

A  DOME  OR  DOMAL  STRUCTURE  :  A  structure  of  this  type 
is  found  to  have  a  central  elevated  area  from  which  the  strata 
slope  in  every  direction.  (See  cut  No.  3,  page  28.)  Such 
condition  is  sometimes  called  a  Quaquaversal  structure.  The 
description  which  applies  to  an  anticlinal  fold  covers  also  the 
disposal  of  the  rocks  over  a  dome,  though  the  inclined  beds 
will  but  rarely  define  a  perfect  mathematical  dome,  as  the  limbs 
of  the  anticline  will  not  often  be  uniform  and  regular.  Some 
of  the  greatest  oil  fields  known  are  upon  domes.  The  related 
earth  forms  are  similar  in  all  such  structures,  though  the  causes 
underlying  the  existence  of  the  dome  are  greatly  different  in 
various  of  them.  An  uplift  of  the  igneous  or  other  deep-lying 
rocks  forms  a  structural  build  of  the  overlying  beds  which  has 
all  the  appearances  of  the  similar  condition  caused  by  the  ex- 
pansion which  is  developed  by  certain  minerals  upon  crystalli- 
zation, such  as  rock  salt  or  gypsum;  the  latter  occupies  about 
one-third  more  space  when  in  a  crystallized  than  when  in  a 
massive  state.  The  enlargement  would  have  the  effect  of 

41 


DESCRIPTION  OF  STRUCTURES 


pushing  up  a  body  of  overlying  material,  as  an  upward  move- 
ment of  the  underlying  mass  would  do.  Some  of  the  great 
fields  of  the  southern  Texas  and  Louisiana  regions,  known  as 
the  Gulf  Coastal  Fields,  owe  their  existence  to  what  are  known 
as  salt  domes.  Oil  accumulation  in  the  porous  beds  of  a  domal 
structure  is  a  result  of  similar  conditions  and  in  obedience  to  the 
same  laws  which  prevail  in  governing  its  accumulation  in  the 
anticline. 

TERRACE  AND  DIP-PLANE  STRUCTURES:  The  terrace 
structure  is  defined  as  that  area  which  embraces  a  leveling  of 
the  strata.  What  is  meant  by  the  description  may  be  briefly 
made  plain  by  noting  that  there  are  many  areas  where  the  gen- 
eral inclination  of  the  beds  has  all  been  tilted  in  one  direction 
over  a  very  wide  region.  Where  the  formations  are  similar  and 
were  deposited  under  identical  conditions,  and  where  the  suc- 
cessive disturbances  occurred  contemporaneously  throughout  the 
region,  and  where  there  does  not  exist  evidences  of  divergent 
and  extraneous  earth  movements,  the  region  is  called  a  geo- 
logical province.  Now,  upon  investigation  of  many  geological 
provinces  it  is  found  that  the  degree  of  inclination  of  the  beds 
is  changed  and  there  are  localized  areas  where  the  strata  lie 
flat.  That  is  a  terrace  such  as  is  known  to  oil  fields.  While 
it  may  be  true  that  after  passing  upward  along  the  inclination 
of  the  beds  falling  away  from  the  terraced  area,  and  across  the 
latter  area  also,  the  beds  will  again  disclose  the  inclination  noted 
further  down  the  dip,  and  that  such  inclination  will  continue  to 
rise  until  the  point  of  action  or  the  apex  of  the  dip-plane  is 
found.  The  fact  remains  that  the  terrace  is  present,  and  that 
oil  will  not  continue  to  pass  along  under  a  level  stratum  or  move 
through  one,  though  it  may  accumulate  in  it  after  it  is  driven 
from  lower  levels  in  the  dip-plane  because  of  the  greater  specific 
gravity  of  water. 


DESCRIPTION  OF  STRUCTURES 


The  Dip-plane  Structure  is  that  area  of  change  of  degree  of 
inclination  of  the  dipping  beds,  and  may  be  present  at  any  point 
along  the  dip  of  the  strata.  Oil  will  move  upward  through  a 
porous  stratum  as  water  passes  to  the  low  levels,  but  will  not 
have  the  freedom  of  action  at  places  where  the  pitch  exhibits 
any  considerable  change  of  degree.  This  type  of  structure  is 
not  as  favorable  as  the  terrace,  though  it  differs  from  it  only  in 
the  fact  of  being  somewhat  removed  from  an  actual  horizontal 
position  of  the  permeable  material  in  which  the  oil  may  be 
contained. 

THE  FAULT  STRUCTURE:  Properly  speaking,  we  do  not 
refer  to  the  faulted  conditions  found  in  nearly  every  region 
where  the  evidences  of  disturbances  are  present  as  a  structure; 
though  a  sealed  fault  into  one  or  the  other  plane  of  which  oil 
may  have  found  access  and  be  impounded,  is  a  form  of  struc- 
ture. Since  some  of  the  very  important  producing  areas  are 
delivering  their  values  from  structures  of  this  type,  it  will  be 
well  to  explain  the  condition  under  which  the  petroleum  may 
gather  and  remain  in  them.  (See  cut  No.  4,  page  38.) 

In  the  first  place,  a  fault  is  a  breaking  of  the  formations  in 
a  more  or  less  nearly  vertical  manner,  and  a  lifting  of  the  strata 
on  one  or  the  other  side,  possibly  upon  both  sides,  but  usually 
with  one  plane  lifted  higher  than  the  other.  The  plane  of 
higher  elevation  is  called  the  up-throw  side,  in  event  it  is  known 
that  the  lower  side  was  not  in  fact  an  actual  down-throw,  leav- 
ing the  other  side  in  place  at  the  time  of  movement.  Now, 
observe  that  if  the  up-throw  plane  of  a  fault  were  to  lift  with 
its  movement  a  porous  stratum  of  material  containing  oil  so  that 
its  edge  rested  against  the  broken  edge  of  a  massive  body  of 
limestone,  or  a  clay  stratum,  or  some  other  impervious  material, 
the  oil  content  of  the  porous  body  would  be  sealed  in  and  would 

43 


DESCRIPTION  OF  STRUCTURES 


stay  in  that  higher  portion  of  the  formation.  If  there  were 
water  on  top  and  oil  on  the  bottom  of  the  formation  so  uplifted, 
the  position  the  bed  would  occupy  after  being  elevated  would 
drain  the  oil  to  the  higher  part  of  the  formation  as  the  water 
settled  to  the  lower  part.  The  present  disclosures  upon  the 
'surface  in  some  of  the  fields  now  producing  from  sealed  fault 
planes  indicate  that  the  oil-bearing  member  was  uplifted  from 
a  position  in  the  earth  so  deep  that  it  could  not  have  been 
reached  by  the  drill;  possibly  also  leaving  the  other  portion  of 
the  elevated  formation  at  the  original  great  depth  from  which 
recovery  would  be  impracticable  if  not  impossible. 

It  may  be  said  that  there  are  other  forms  of  structure  known 
which  are  uncommon,  and  doubtless  yet  others  exist  the  type  or 
form  of  which  we  do  not  know ;  but  the  foregoing  gives  a  fairly 
good  idea  of  the  most  prevalent  types  met  with  in  various  of  the 
great  producing  fields.  Something  about  the  natural  processes 
of  oil  movement  in  the  ground  so  that  it  gathers  into  catchment 
reservoirs  will  be  of  interest. 


44 


CHAPTER  VI 

OIL  ACCUMULATION  AREAS,  HOW 
DETERMINED 

SOME  INSTANCES 

Petroleum  as  it  is  found  in  the  ground  in  local  accumulations 
represents  the  results  of  gathering  processes  which  are  operative 
by  reason  of  certain  laws  of  Nature  which  are  pretty  well 
understood.  It  is  believed  that  the  great  amount  found  in  the 
many  fields  of  the  world  were  at  first  in  very  small  particles  or 
drops  in  the  formations  which  bore  the  antecedent  possibilities  of 
oil  making;  also  that  such  formations  may  or  may  not  have 
occupied  a  level  position  then,  and  that  water  was  also  in  the 
formations  at  that  time  or  was  later  admitted  to  them.  It  is 
known  that  petroleum  migrates  to  elevated  positions  above 
water  whether  it  be  on  the  surface  of  the  ground  or  in  sub- 
surface levels.  It  is  also  true  that  nearly  all  strata  have  been 
shifted  and  tilted  out  of  a  horizontal  position,  and  that  such 
position  offers  the  condition  which  provides  for  separation  of 
water  and  oil  by  natural  activities  known  to  have  been  present 
in  the  earth  throughout  its  past,  and  not  absent  in  this  age. 

45 


LOCATIONS  IN  NEW  REGIONS 


Upon  the  foregoing  knowledge  and  its  .application  to  the 
earth  picture  of  an  area  every  location  for  a  drill  in  a  new 
region  should  be  based.  It  is  needless  to  say  that  a  great  many 
test  wells  are  drilled  without  regard  to  the  existence  of  such 
information,  and  that  possibly  one  out  of  every  two  or  three 
hundred  of  them  find  oil  in  profitable  quantity.  The  percentage 
of  successful  wells  drilled  in  new  areas  selected  by  experienced 
and  capable  geologists  after  they  have  determined  that  petro- 
leum-bearing formations  are  present  in  the  area  is  relatively 
very  large ;  probably  out  of  every  one  hundred  such  wells  drilled, 
ninety  of  them  find  oil  in  commercially  profitable  amount. 
Statistics  of  oil  discoveries  of  late  years  appear  to  fully  bear 
out  that  statement.  During  1920  it  is  reported  that  21  new 
oil  fields  were  discovered  in  the  United  States,  and  that  20  of 
them  were  drilled  in  areas  and  at  locations  selected  by  geol- 
ogists. It  may  be  well  to  make  a  brief  statement  of  some  of 
the  more  important  considerations  which  must  be  remembered 
if  one  would  safely  locate  areas  in  which  petroleum  may  exist 
in  commercial  quantities,  and  would  properly  select  the  site  for 
the  drilling  of  the  first  wells  in  that  area. 

1 .  Determine  if  the  area  is  underlain  with  oil-making  for- 
mations, and  if  so,  if  such  formations  are  in  contact  with  or  so 
located  in  the  sub-surface  area  as  to  allow  the  migration  of  any 
petroleum  content  to  porous  formations  which  may  act  as  reser- 
voirs for  the  accumulation  and  retention  of  it. 

Develop  a  knowledge  of  the  foregoing  conditions  by  a  careful 
examination  of  all  exposures  of  the  formations  which  indicate 
that  they  are  present  under  the  area.  Learn  if  such  formations 
are  actually  productive  of  oil  in  any  area  in  the  geological  prov- 
ince which  includes  it.  Examine  the  identities,  similarities  and 
differences  of  the  formations  exposed  as  to  their  lime,  sand  or 

46 


HOW  TO  FIND  STRUCTURES 


shale  character,  their  looseness,  porosity,  density,  etc.,  as  com- 
pared to  the  same  formations  from  which  oil  is  being  taken  out 
of  profitable  wells  in  all  related  areas. 

2.  Determine  as  far  as  possible  if  any  area  in  the  province 
shows  arching,  doming  or  terracing  of  the  strata  which  include 
the   petroleum-making    and    the    petroleum-bearing    formations 
which  the  investigation  outlined  above  has  identified. 

3.  Measure  the  degree  of  dip,  the  direction  of  the  inclina- 
tion, the  thickness  of  the  various  sandstone,  lime  and  shale  for- 
mations, and  determine  definitely  if  there  actually  be  a  folding 
of  the  rocks,  or  a  possible  elevated  condition  of  the  sub-surface 
strata  indicated;  and  if  so,  if  there  be  adequate  thickness  of  the 
oil-producing  and  porosity  of  the  oil-bearing  members  to  war- 
rant the  conclusion  that  the  possible  output  may  be  in  profitable 
amount. 

4.  Note  on  a  map  of  the  area  the  corners  of  sections  and 
other  sub-divisions  of  the  land,  and  with  relation  thereto  mark 
the  places  of  outcrop,  what  rocks  are  exposed,  what  their  incli- 
nation may  be  as  to  degree  of  dip  and  direction  and  to  what 
extent  disclosed.     Use  pencils  of  different  colored  lead  for  the 
different  formations. 

5.  Proper  use  of  the  Aneroid  Barometer  will  give  eleva- 
tions, which  should  be  noted  on  the  map  as  the  formations  are 
spotted,  so  that  the  level  of  any  given  formation  will  be  seen 
at  a  glance  throughout  an  area  the  size  of  a  small  ranch  or  as 
extensive  as  a  county. 

6.  One  must  be  assured  by  sufficient  examination  to  decide 
if  any  possible  arch  or  dome  might  have  been  caused  by  the 
presence  of  some  mineral  in  the  sub-surface  levels,  such  as  beds 
of  salt  or  gypsum,  which  increase  in  size  while  crystallizing  and 

47 


HOW  TO  FIND  STRUCTURES 


produce  effects  in  overlying  formations  similar  to  such  effects 
caused  by  folding  and  buckling  of  the  deeper  formations.  Also, 
the  possibility  of  ancient  landslides  having  left  effects  which 
may  be  similar  to  the  change  of  pitch  found  in  terrace  and  dip- 
plane  structures,  or  the  reversal  of  dip  as  found  in  anticlinal  or 
domal  structures  must  be  carefully  noted.  But  such  superficial 
displacements  of  the  strata  are  usually  easy  and  certain  of 
determination,  though  they  must  not  be  neglected. 

7.  Examine  the  area  along  the  apex  of  the  anticline  and 
at  either  extremity  of  it  to  determine  if  it  is  closed,  so  that  any 
accumulation  which  may  ever  have  drained  into  it  is  still  present. 

This  may  usually  be  definitely  ascertained  by  noting  if  the 
inclined  beds  again  resume  their  normal  dip  after  the  uplifted 
areas  have  been  passed;  or  by  a  fault  zone  which  has  forma- 
tions exposed  in  one  or  the  other  of  its  planes  which  are  of  an 
impermeable  character ;  or  if  the  inclination  of  the  rocks  is  away 
from  the  apex  of  the  fold  at  the  ends ;  or  if  sealed  non-conform- 
able contacts  are  present,  thus  cutting  off  the  possibility  of 
escape  of  the  oil. 

Terrace  and  dip-plane  structures  will  in  almost  all  cases  be 
naturally  closed  to  prevent  the  wastage  of  the  oil  content  to  the 
surface  by  reason  of  the  peculiar  forms  of  such  structures.  To 
learn  if  a  fault  be  sealed  so  that  the  one  or  the  other  plane  of 
it  will  hold  oil  if  any  were  in  it  or  has  drained  into  it,  is  a  matter 
of  the  most  careful  field  investigation,  and  the  methods  are  so 
complex  and  the  usual  earth  forms  are  so  broken  up  and  dis- 
torted that  it  is  impracticable  to  undertake  to  describe  condi- 
tions upon  which  a  conclusion  might  be  based  as  to  whether 
the  fault  actually  does  seal  the  structure  or  leave  it  open.  Upon 
that  point,  however,  the  field  examination  must  proceed  to  a 
degree  of  definite  satisfaction. 

48 


RULES  TO  OBSERVE 


The  type  of  structure  will  be  determined  in  most  cases  at 
the  first  glance  over  a  region,  if  any  be  present ;  but  its  character 
and  exact  form,  and  the  various  disclosures  shown  on  the  surface 
denoting  the  extent  of  the  inequalities  and  displacements  of  the 
underground  picture,  must  be  examined  with  the  utmost  care, 
and  exactly  mapped. 

It  is  now  seen  that  every  type  of  oil  structure  confirms  the 
following  assumptions  and  appears  to  provide  for  the  operation 
of  the  laws  of  gravity,  though  with  respect  to  the  latter  there 
will  be  found  many  qualifying  conditions  and  determining 
factors  involved. 

Let  us  state  the  matter  in  short  sentences : 

1 .  The  beds  must  incline  from  a  horizontal  position. 

2.  There    must    be    beds    present    in    which    petroleum 
originates. 

3.  The  possible  gathering  area  must  be  extensive. 

4.  The  generating  formations  must  be  in  some  manner  in 
contact  with  the  porous  formations  which  act  as  catch- 
ment reservoirs. 

5.  Impermeable  formations  must  in  some  manner  enclose 
the  latter. 

6.  Adequate  thickness  must  exist  in  the  oil-making  forma- 
tions. 

7.  Matters  of  feasibility  and  practicability  of  access  to  the 
world  are  important. 

8.  Petroleum  in  many  instances   is  found  impounded  by 
water  in  a  syncline  (a  relatively  low  area  with  reference 
to  adjacent  strata). 

9.  Oil  may  be  driven  by  water  into  a  trap  formed  by  a 
fault  wall  or  a  non-conformable  deposit  which  is  im- 
pervious. 

49 


50 


In  cut  No.  5  one  limb  of  an  anticline  is  shown.  In  the  bank 
of  the  stream  at  the  right  of  the  horse  the  inclination  of  the  beds 
is  well  developed.  In  the  extreme  background  at  the  left  of 
the  horse,  in  the  side  of  the  hill,  the  level-lying  formations  are 
well  pictured.  Evidently  the  tilting  strata  of  the  anticline  pass 
under  the  latter  formations,  but  the  level  strata  do  not  dip  con- 
formably with  the  formations  in  the  limb  of  the  fold  at  the 
right. 

In  nearly  all  cases  similar  to  the  earth  picture  shown  in  the 
cut  it  will  be  found  that  there  is  an  unconformity  in  the  top 
formations.  That  is  to  say,  after  the  forces  were  expended 
and  the  anticline  was  formed,  later  sedimentation  occurred  and 
beds  were  put  down  in  a  horizontal  position,  the  ends  of  which 
lie  in  that  level  manner  against  the  formations  which  define  the 
tilting  beds  of  the  anticline.  In  all  such  cases  it  is  of  moment 
to  determine  to  what  depth  such  non-conformable  formations 
reach,  and  what  rock  stages  are  embraced  in  the  unconformity. 
Usually  the  line  of  unconformity  may  be  readily  determined, 
and  from  the  facts  it  will  not  be  difficult  to  decide  if  accumu- 
lation a*reas  for  oil  might  have  been  provided  along  such  line. 


51 


DIASTROPHIC  ACTION 


10.  Like  all  other  fluidic  substances  in  or  upon  the  ground, 
oil  will  seek  the  lowest  accessible  level,  and  if  water  be 
absent,  it  will  settle  in  time  into  any  trough  (syncline) 
formed  by  the  strata. 

With  respect  to  paragraph  4,  it  may  be  explained  that  the 
originating  formation  may  lie  very  distant  indeed  from  the  for- 
mation in  which  we  find  the  oil  when  we  drill;  but  the  fact  of 
accessibility  is  not  thereby  absent.  The  travel  or  migration  of 
oil  through  a  formation  may  have  covered  a  short  or  a  very 
great  distance  before  being  impounded  in  some  character  of 
natural  trap  in  the  earth.  (See  cut  No.  6). 

There  is  a  very  interesting  theory  to  account  for  the  presence 
of  petroleum  accumulations  which  has  lately  been  advanced  by 
Marcel  Daly.  It  is  known  as  the  "Diastrophic"  theory,  and 
may  be  presented  with  some  clearness  by  illustration.  If  we 
squeeze  a  mass  of  sugar  saturated  with  water,  the  latter  will 
be  forced  out;  as  when  we  wring  a  water-soaked  cloth,  the 
water  leaves  it. 

As  has  been  said,  the  earth  is  not  solid,  but  is  made  up  as 
to  its  crust  by  alternating  harder  and  softer  formations  of  vary- 
ing characteristics;  some  are  very  thin  and  massive,  others  are 
thick  and  porous,  and  still  others  are  modifications  of  the 
qualities  of  one  or  the  other.  When  the  tremendous  forces  are 
exerted  in  Nature's  vast  power  stations  which  are  adequate  to 
the  disturbance  of  extensive  areas  of  the  surface  and  sub-surface 
strata,  it  appears  possible  that  any  petroleum  in  the  formations 
affected  might  be  squeezed  or  wrung  out.  It  would  not  follow 
that  it  would  be  forced  to  the  surface  or  wasted,  but  it  might 
well  be  driven  into  areas  of  the  formations  adjacent,  over,  at 
one  side,  or  upon  the  sides,  or  possibly  under  the  formations, 
which  felt  the  force  of  the  action.  Even  so,  the  petroleum 

52 


HOW  TO  KNOW  OIL  STRUCTURES 


could  conceivably  be  retained  in  formations  within  the  axis  of 
action,  but  in  less  space  as  compared  to  its  scattered  condition 
before  the  earth  movement. 

Examination  of  the  illustrations  throughout  the  book  will 
convey  a  good  idea  of  the  appearance  of  a  large  number  of 
areas  near  oil  fields  and  elsewhere  throughout  the  United 
States.  In  the  first  picture,  on  page  1  6,  the  topography  is  well 
shown.  In  the  second  the  diagram  indicates  the  place  occupied 
by  each  formation  with  relation  to  underlying  and  overlying 
strata.  Also,  in  the  second  the  outcropping  beds  could  be 
examined  as  to  character,  thickness  and  relative  position,  as  to 
inclination  and  direction  of  dip,  as  we  walked  up  the  side  of 
the  elevation  shown  in  the  middle  of  the  top  of  the  picture,  if 
we  were  going  toward  the  east.  If  we  were  going  toward  the 
west  from  the  base  of  the  hill  shown  at  the  right-hand  side  of 
the  picture,  we  would  walk  upon  the  Mancos  shale  to  the  sum- 
mit of  the  hill  unaware  as  to  what  beds  might  lie  under  it,  or 
indeed  as  to  what  position  they  might  occupy,  and  could  not 
have  knowledge  as  to  their  character.  Oil  accumulation  in 
an  area  like  this  could  have  been  caused  by  Diastrophic  action. 

Now,  assume  that  the  Dakota  sandstone  outcrop  near  the 
summit  of  the  hill  shown  in  the  middle  of  the  top  of  the  picture 
could  be  followed  along  the  surface  for  ten  or  a  hundred  miles 
as  the  case  might  be,  somewhat  as  its  upturned  edges  have  been 
traced  by  the  writer  about  the  slopes  of  the  Black  Hills  of 
South  Dakota  and  Wyoming  for  a  greater  distance  than  the 
maximum  stated;  suppose  also  that  in  a  nearby  area  oil  was 
being  taken  in  profitable  quantities  from  wells  which  found  the 
saturated  horizons  in  the  Dakota  sandstone,  and  that  it  had 
been  found  that  the  productive  area  occupied  a  place  where 
the  sandstone  had  been  uplifted  above  its  normal  position,  and 

53 


HOW  TO  KNOW  OIL  STRUCTURES 


that  the  overlying  strata  was  of  an  impervious  character,  and 
that  the  last  named  formation  was  exposed  lying  over  the  sand- 
stone farther  up  the  hill;  it  would  be  known  that  the  sandstone 
with  the  massive  material  overlying  it  would  occupy  relative 
positions  throughout  the  general  region;  now,  suppose  that  we 
are  at  position  A,  and  the  imaginary  oil  field  mentioned  is 
40  miles  southeast  of  us  at  position  B,  and  that  30  miles  north- 
west of  us  at  C,  or  some  60  miles  north  of  B,  there  is  a  defined 
anticline  or  dome,  the  inference  would  be  strong  that  an  oil 
field  could  also  be  opened  at  C.  Then  the  examination  would 
proceed  to  the  determination  of  every  factor  involved  in  the 
strata  and  their  character  and  relative  position  in  the  entire 
region,  before  decision  could  be  made  as  to  the  probabilities  of 
finding  oil  in  paying  quantity  in  the  new  area.  However,  new 
oil  fields  are  located  with  much  greater  assurance  in  the  manner 
stated  than  in  any  other  way.  It  will  be  found  that  nearly  all 
of  the  problems  which  will  be  involved  in  arriving  at  depend- 
able conclusions  with  reference  to  the  probabilities  of  profitable 
oil  accumulation  in  new  areas  have  now  been  touched  upon. 


54 


CHAPTER  VII 
SUMMARY,  PROBABLE  NEW  FIELDS. 

In  the  illustration  shown  in  cut  No.  5,  the  inclina- 
tions of  the  beds  are  plainly  seen  in  the  hillside  in  the  right 
background  from  the  horse.  When  following  such  strata 
throughout  an  extensive  region  it  is  always  well  to  select  certain 
beds  as  horizon  markers.  By  that  we  mean  to  say,  certain 
members  which  are  distinctive  by  reason  of  color,  size  of  grains 
and  all  other  features  which  render  them  certain  of  identifica- 
tion, in  order  that  we  may  be  assured  that  the  same  formation 
and  an  identical  part  of  that  formation  is  being  followed.  It  is 
possible  to  secure  the  exact  levels  above  or  below  some  selected 
datum  line  of  any  part  of  a  designated  formation  throughout 
every  part  of  a  region  if  the  formation  is  exposed  at  intervals, 
even  if  covered  in  places  by  hills  or  removed  at  other  places  by 
erosional  processes. 

55 


The  diagram  showing  an  excellent  vertical  section  of  non- 
conformable  strata,  pictured  in  cut  No.  6,  is  selected  from 
U.  S.  Geol.  Sur.  Bulletin  647,  and  represents  one  of  the  best 
illustrations  of  that  form  of  earth  picture  available  to  the  writer. 
Indeed,  all  of  the  pictures  reproduced  in  this  booklet,  except 
cut  No.  7,  first  appeared  in  Government  publications. 

It  will  be  seen  that  the  position  of  the  beds  lying  against  the 
andesite  of  the  Livingston  formation  could  not  be  known  except 
by  drilling  at  many  places,  or  because  of  their  exposures  at 
many  localities  in  the  related  geological  areas. 

Various  local  areas  in  Texas,  such  as  the  productive  district 
adjacent  to  Desdamona,  in  the  Electra  area,  in  the  developing 
areas  along  the  Marathon  Fold  in  the  west-central  portion  of 
the  State,  Mitchell  County,  etc.,  first  investigated  and  mapped 
by  the  present  writer  in  1919,  are  expressive  of  many  uncon- 
formities. It  has  been  essential  to  such  knowledge  to  compare 
drill  cuttings  from  many  wells,  though  the  general  fact  was 
determined  by  geological  investigation.  In  and  around  the 
great  Healdton  oil  field  in  Oklahoma  the  drills  have  provided 
accurate  information  of  lines  of  unconformity,  though  at  the 
time  of  the  first  examination  of  the  area,  when  the  writer  made 
the  location  upon  which  the  discovery  well  was  drilled  about 
twelve  years  ago,  many  lines  of  unconformity  were  indicated  in 
the  report  upon  the  region. 

Formations  lying  upon  rocks  of  older  or  younger  stages  ex- 
press such  interrupted  age  position  to  good  advantage  where 
several  *beds  are  exposed  in  deep  depressions,  and  along  hill- 
sides which  embrace  considerable  areas  in  their  slopes. 


57 


FORMATION  EXPOSURES 


The  diagram  shown  in  cut  No.  6,  clearly  sets  out 
the  position  of  the  beds  underground  in  an  area  familiar  to  the 
writer.  At  points  many  miles  distant  in  different  directions 
some  of  these  strata  are  exposed.  At  other  places  others  of 
them  are  exposed,  and  at  still  other  places  others  are  upturned 
to  the  surface.  It  is  by  noting  such  conditions  with  relation  to 
other  stratigraphic  and  lithologic  facts  that  we  are  able  to 
determine  with  a  reasonable  degree  of  certainty  what  beds  were 
to  some  extent  wasted  away  before  later  beds  were  put  down 
over  them,  causing  what  is  termed  an  unconformity.  That 
determination  is  in  some  regions  impossible,  though  there  are 
yet  other  methods  involving  many  complex  and  baffling  prob- 
lems which  may  be  employed  in  arriving  at  working  conclusions. 
They  are  too  intricate  to  admit  of  treatment  here. 

The  diagram  shown  in  cut  No.  7,  is  a  vertical  chart 
of  the  formations  embraced  in  a  structure  of  the  anti- 
clinal type  investigated  by  the  writer  recently  for  a  California 
oil  company.  The  area  lies  in  the  geological  province  which 
includes  the  productive  district  of  Coalinga,  and  in  the  main 
embodies  identical  formations  with  the  last  named  oil  fields. 

Disclosed  by  the  exposures  of  the  uplifted  Tejon  sandstone 
formation  of  the  Eocene  deposits,  the  first  sedimentation  of  the 
Tertiary  period,  the  anticline  passes  southeastward  from  near 
the  middle  of  Section  3,  Township  6  South,  Range  7  East,  in 
the  foothills  west  of  Patterson,  Stanislaus  County,  California, 
in  a  definite  arc  to  a  final  southwesterly  direction,  ending  in 
the  southward  tilting  beds  along  the  south  line  of  Sections  35 
and  36  of  the  township  and  range  named.  It  underlies  ap- 
proximately 9,000  to  1  1 ,000  acres.  The  Moreno  shales,  the 
last  deposit  of  the  Upper  Cretaceous  formations  in  that  region, 
underlie  the  sandstone  mentioned.  It  is  known  to  be  a  petro- 

58 


SALADO  ANTICLINE  DESCRIBED 


leum-making  formation  and  to  be  delivering  oil  in  profitable 
amount  from  wells  in  the  Coalinga  district. 

The  last  named  formation  is  principally  shale,  though  sand 
lenses  exist  in  it.  The  first  formation  named  is  principally  a 
sandstone  body,  though  shale  members  of  varying  thickness  are 
found  in  it 

It  is  noted  that  these  formations  lie  in  proper  relative  position 
for  the  gathering  of  petroleum  into  the  upper  out  of  the  lower 
strata.  The  Moreno  is  known  to  be  organic  and  is  equally 
known  to  produce  oil.  The  Tejon  is  of  a  porous  character,  as 
all  sands  are  to  a  greater  or  less  degree.  The  beds  lie  in  a 
series  of  inclined  strata  which  dip  towards  the  east  away  from 
the  apex  of  the  Coast  Range,  it  being  possible  to  follow  their 
upturned  edges  from  the  Coalinga  district  to  the  area  of  the 
structure  west  of  Patterson  as  described. 

Lying  towards  the  east  is  the  San  Joaquin  Valley,  under 
which  the  beds  lie,  as  has  been  determined  by  reason  of  their 
exposed  edges  on  the  east  side  of  the  valley  where  they  have 
been  uplifted  along  the  slopes  of  the  Sierra  Nevada  Mountains. 

The  extent  of  the  formations  throughout  the  region  from 
which  petroleum  may  have  been  gathered  by  drainage  into  the 
structure  is  very  great,  being  possibly  as  much  as  150  square 
miles  in  areal  dimension  at  their  sub-surface  level.  The  thick- 
ness of  the  Moreno,  which  is  the  oil-making  member,  is  some- 
what near  a  possible  average  of  800  feet ;  hence  the  possibilities 
of  the  anticline  containing  oil  in  profitable  amount  appear  very 
well  founded  indeed. 

In  San  Joaquin  Valley  towards  its  eastern  border,  a  con- 
siderabfe  distance  from  Bakersfield,  the  writer  has  investigated 
a  structure  which  it  is  thought  contains  an  accumulation  of  oil, 
and  which  will  in  time  no  doubt  be  exploited  by  test  drilling. 

59 


PROBABLE  NEW  OIL  FIELDS 


South  of  Devil's  Den,  west  of  the  Lost  Hills  field,  another 
structure  has  been  examined  which  should  contain  oil  in  profit- 
able amount.  It  now  has  a  drill  located  upon  it  at  a  point 
which  it  is  thought  will  prove  its  possible  value.  A  consider- 
able distance  southeast  of  the  anticline  described  west  of  Pat- 
terson, in  Township  6  South,  Range  7  West,  which  was  called 
the  Salado  Anticline  by  members  of  the  United  States  Geolog- 
ical Survey  in  Bulletin  No.  603,  there  are  evidences  pointing  to 
a  very  extensive  anticlinal  fold,  which,  if  actually  present,  is 
ideally  located  to  have  gathered  an  accumulation  of  oil  of  large 
proportions.  % 

The  writer  believes  that  there  are  oil  fields  in  California,  as 
well  as  in  the  mid-western  States,  which  have  not  been  opened, 
basing  that  opinion  upon  many  more  or  less  critical  investigations 
made  during  the  past  20  years.  As  to  California,  it  appears  that 
there  might  be  profit  resulting  from  more  detailed  and  careful 
investigation  of  various  areas  in  and  along  the  borders  of  Sac- 
ramento Valley,  where  the  formations  are  in  many  places  similar 
and  in  some  places  identical  with  formations  in  the  south  valley. 
There  are  areas  where  structural  conditions  warrant  the  opinion 
that  oil  accumulations  exist,  and  such  regions  constitute  an 
integral  portion  of  the  varied  and  wonderfully  rich  domain 
known  and  loved  by  us  as  California.  In  Texas,  Louisiana, 
Oklahoma,  Kansas  and  New  Mexico,  including  areas  in  Illinois 
where  critical  examinations  have  been  made,  the  writer  knows 
of  localities  where  new  fields  will  probably  be  opened. 

With  the  constantly  increasing  number  of  avenues  into  which 
the  refined  products  of  crude  petroleum  are  poured,  and  the 
ever-widening  and  extending  necessities  of  expanding  industries 
essential  to  the  prosperity  of  the  race,  there  appears  to  be  an 
equal  broadening  of  the  opportunities  for  great  wealth  held 
ready  for  the  intelligent,  capable  and  straightforward  oil  field 
promoter.  ^ 


MUCH  FUTURE  OIL  OUTPUT 


Falling  within  the  experiences  of  the  present  writer  through- 
out an  active  professional  life  extending  to  all  of  the  oil- 
producing  regions  of  the  United  States,  he  has  seen  very 
few  men  indeed  who  failed  of  success  in  the  oil  fields  if 
their  purposes  were  clean  and  logical,  if  their  good  names 
were  kept  good,  if  they  were  counseled  by  scientific  advisers 
of  experience  and  ability,  and  if  they  followed  with  deter- 
mination the  rapidly  opening  fields  of  this  great  industry. 

While  it  appears  true  that  the  known  sources  of  great  oil 
production  are  being  rapidly  depleted  throughout  the  country, 
it  is  equally  true  that  there  are  a  very  large  number  of  regions 
in  many  of  the  States  where  the  present  writer  has  in  times  past 
made  critical  and  extensive  investigations,  some  of  which  will 
quite  surely  be  opened  to  production  and  which  will  deliver 
quantities  of  oil  for  the  enlarging  needs  of  the  world,  and  will 
in  equal  measure  make  and  break  promoters  in  about  the  estab- 
lished ratio  of  the  past.  He  that  drills  at  random  will  in  many 
cases  lose,  while  he  that  drills  upon  proper  counsel  will  in  most 
cases  win. 

The  United  States  may  be  kept  at  the  fore  for  many  years 
in  oil  production  among  the  nations  of  the  world.  California 
may  be  kept  in  the  lead  for  many  years  in  oil  production  among 
the  States  of  the  Union. 

Pacific  shore  lands  will  be  the  most  active  portion  of  the 
world  throughout  the  next  century  or  longer.  California  is  on 
Pacific  waters. 


61 


l^l^Hp^'Hlf  ^, 


62 


The  diagram  shown  by  cut  No.  7  was  prepared  by  the 
present  writer  for  a  California  oil  company,  and  is  representa- 
tive of  a  general  vertical  section  of  San  Joaquin  Valley  and  the 
foothills  of  the  Coast  Range  along  the  western  border  of  the 
valley. 

It  will  be  understood  that  no  possible  knowledge  available 
in  advance  of  drilling  would  be  adequate  to  the  exact  determi- 
nation of  the  precise  line  where  any  given  underlying  formation 
is  cut  out,  though  sufficiently  dependable  information  of  such 
probable  line  would  be  obtainable  by  examination  of  the  whole 
area  lying  along  the  western  border  of  the  valley. 

Referring  to  the  diagram,  it  may  be  said  that  the  formations 
grouped  near  the  surface,  beginning  with  the  bottom  of  the 
Kreyenhagen  shale  and  inclusive  of  the  overlying  Vaqueros, 
Santa  Margarita  and  Etchegoin  (horizon),  are  unmistakably 
absent  at  a  point  in  the  picture  which  may  be  pointed  out  as 
the  top  of  the  oval  hill  shown  under  the  word  "East.'*  The 
diagram  was  intended  to  predicate  the  general  position  of  the 
formations  along  the  western  border  of  the  valley,  but  with 
direct  reference  to  the  location  and  character  of  Salado  Anti- 
cline west  of  Patterson.  The  Tejon  formation  is  known  to 
be  disposed  on  the  surface  in  some  places  along  the  apex  of 
the  anticline,  though  in  many  places  it  is  hidden  by  a  thin 
covering  of  the  San  Pablo.  Exposures  of  the  edges  of  the 
inclined  beds  immediately  west  of  the  anticline  are  proof  of 
the  absence  or  presence  of  certain  of  the  otherwise  sequent 
deposits  embraced  in  the  fold.  Such  upturned  edges  when 
followed  southward  to  the  productive  fields  indicate  with  equal 
assurance  the  recurrent  lines  of  unconformity  indicated  in 
the  cut 

63 


CHAPTER  VIII 

NOTES  ON  OIL  COMPANY  PROMOTION  AND 
RELATED  SUBJECTS 

THE  lure  of  quick  returns  and  great  riches  appears  to  be 
the   compelling   attraction   which   turns    the   efforts   of 
many  promoters  in  the  direction  of  oil  company  promo- 
tions.    The  drilling  of  oil  wells  throughout  the  United  States 
and  elsewhere  in  the  world  has  been  made  into  a  history  of 
spectacular  delight  to  the  shrewd  men  whose  energies  are  given 
to  the  enterprise. 

The  Bulletins  of  the  United  States  Survey,  and  the  Profes- 
sional Papers,  Reports  and  Statistical  Reviews  published  by 
the  Department,  together  with  the  annals  of  the  oil  fields  every- 
where, have  supplied  documentary  evidence  in  quantities 
amounting  to  actual  proof  of  the  tremendous  riches  hidden  in 
the  oil  industry — when  such  documents  are  subjected  to  the 

64 


PAYING  WELLS  AND   LOSING  WELLS 


winnowing  processes  employed  by  men  whose  wish  is  to  uncover 
the  promises  and  neglect  the  snares  that  inhabit  the  business. 

It  will  be  admitted  that  if  a  statistician  is  actuated  by  a  desire 
to  establish  the  very  high  percentage  of  paying  wells  to  the 
whole  number  of  wells  drilled  in  any  good  paying  field,  the 
facts  extant  upon  the  subject  provide  the  necessary  material  to 
amass  the  proofs  needed.  If  such  array  of  established  facts 
relative  to  some  special  field  be  applied  to  the  fields  in  general 
throughout  the  country  it  will  be  found  that  the  ratio  of  paying 
wells  is  rated  entirely  too  high.  If,  again,  such  ascertained 
facts  be  applied  to  the  possible  fields  throughout  the  country 
and  to  regions  where  oil  is  possible  of  occurrence  in  profitable 
quantity  but  has  not  yet  been  discovered,  the  hypothetical  infer- 
ence will  bear  no  relation  to  the  real  facts. 

This  is  equivalent  to  saying:  If  we  assume  that  there  were 
a  total  of  5,657  wells  drilled  in  the  old  Glenn  Pool  in  Creek 
County,  Oklahoma,  and  of  that  number  it  is  found  that  95  per 
cent  of  them  were  paying  wells,  and  that  by  reason  of  that 
established  fact  we  may  expect  95  per  cent  of  the  wells  to  be 
drilled  within  the  area  of  any  oil-producing  State  will  be  paying 
wells,  it  will  be  found  that  our  estimates  are  very  much  awry. 

If  we  further  assume  that  a  vast  lot  of  wildcat  drilling  is 
being  done  in  a  region,  say  for  illustration,  in  the  State  of  Texas, 
and  we  are  possessed  of  the  knowledge  that  that  State  has  about 
40  fields  where  oil  in  commercially  profitable  amount  is  being 
produced,  and  is  generally  known  to  be  a  region  favorable  for 
oil,  it  does  not  of  necessity  follow  that  the  same  percentage  of 
paying  wells  will  be  found  in  the  wildcat  areas  to  the  whole 
number;  of  wells  drilled  that  will  be  found  in  the  more  nearly 
proved  districts. 

Suppose  that  there  are  4,000  wells  actually  under  the  drill 

65 


PERCENTAGES  OF  SUCCESS 


at  any  given  time  in  the  entire  country,  but  that  of  the  whole 
number  stated  four-fifths  of  the,m  are  drilling  in  partially  proved 
and  proved  areas,  the  others  are  drilling  in  unproved  regions. 
This  would  mean  that  about  3,200  of  the  drills  are  at  work 
in  areas  where  oil  should  be  found,  while  800  of  them  are  in 
areas  where  the  possible  oil-bearing  formations  are  so  far  un- 
tested. Actual  facts  heretofore  proved  by  drilling  in  a  vast 
number  of  districts  throughout  the  United  States  appear  to 
have  shown  that  of  the  3,200  wells  somewhat  near  90  per  cent 
of  them  may  expect  oil  in  paying  quantity ;  the  800  in  unknown 
regions  may  expect  a  possible  8  wells  out  of  the  entire  lot. 
Now,  it  will  be  noted  that  the  percentages  of  dry  holes  to 
paying  wells  out  of  the  whole  number  drilling  would  be  but 
little  changed,  though  nearly  all  of  the  profitable  wells  would 
actually  be  found  in  the  areas  where  oil  is  a  most  reasonable 
expectation  because  of  its  known  presence  in  the  geological 
complex. 

The  tremendous  excitement  which  attends  the  bringing  in  of 
a  big  field  in  a  new  area  has  the  effect  of  immediately  setting 
the  promoters  busy  in  acquiring  leases  and  starting  the  drill  in 
many  impossible  regions,  of  some  relation  in  some  cases  to  the 
known  facts  of  the  productive  area,  and  in  other  cases  of  no 
known  relation  to  them  whatsoever.  It  is  admitted  that  some- 
times new  fields  are  really  opened  by  such  indiscriminate  drill- 
ing, but  in  proportion  to  the  whole  number  of  such  untoward 
attempts  the  successes  are  very  rare. 

In  arriving  at  a  dependable  opinion  relative  to  the  ratio  of 
profitable  wells  to  the  whole  number  of  wells  drilling  in  any 
given  State  it  is  essential  to  ascertain  how  many  such  tests  are 
being  put  down  in  regions  where  oil  has  not  yet  been  proven, 

66 


EARLY  OIL  FIELD  SCIENCE 


usually  distant  from  present  oil  production,  as  distinct  from  the 
tests  that  may  be  drilling  in  proved  and  partially  proved  areas. 

An  experienced  scientist  will  usually  be  equipped  with  the 
knowledge  necessary  to  determine  if  good  opportunity  to  dis- 
cover oil  exists  in  an  untried  region  though  it  may  be  distant 
from  present  oil  output;  but  such  information  would  be  too 
much  to  expect  of  any  man  whose  training  and  information 
do  not  include  expert  knowledge  of  geological  formations  and 
structures  which  are  adequate  to  the  making  and  impounding  of 
oil. 

Wholly  aside  from  the  aspect  of  the  geologist's  profession  as 
an  economic  asset  to  the  oil-producing  industry,  there  exists  an 
ethical  side  to  the  matter.  Such  subjects  are  often  treated  by 
learned  men  in  the  journals  and  other  publications  of  a  scientific 
character  devoted  to  the  professions,  but  it  is  not  often  that  we 
see  the  matter  mentioned  in  mediums  of  general  circulation. 

Except  by  a  few  world-renowned  geologists  it  was  not 
thought  that  the  science  of  geology  could  have  any  relation  to 
the  knowledge  of  oil  well  drilling  and  oil  production,  until  long 
after  the  output  of  oil  in  America  became  very  great.  The 
first  well  drilled  for  oil  in  the  United  States  was  at  Titusville, 
Pennsylvania,  in  1859.  Thereafter  during  a  period  of  15  to 
20  years  the  industry  was  feeble,  undergoing  the  formative 
stages  through  which  nearly  all  new  things  of  an  economic  char- 
acter pass.  Extensive  fault  planes  partly  determined  the  direc- 
tion and  width  of  the  oil  accumulation  areas  in  the  first  great 
Pennsylvanian  fields,  and  as  the  drilling  progressed  along  the 
plane  in  which  the  oil  was  impounded  it  was  found  that  profit- 
able wells  were  opened.  If  the  drilling  diverged  from  that  line 
there  were  dry  holes.  That  fact  gave  rise  to  what  the  drillers 
called  "Oil  Lines."  Wells  were  located  in  new  areas  by  the 

67 


GEOLOGY  AND  OIL  LOCATING 


simple  process  of  placing  a  ruler  upon  the  map  of  a  region  so 
that  its  edge  passed  through  the  productive  areas,  the  proposed 
wells  being  spotted  on  ahead  of  known  production  along  the 
line  mentioned.  Geologists  were  derided — the  old  Pennsyl- 
vania driller  had  small  use  for  the  profession;  his  father  found 
oil  without  science  and  what  his  father  did  was  good  enough 
for  the  son. 

During  the  early  years  of  the  Kansas  fields  many  locations 
were  made  with  the  rule  and  map.  Drilling  near  Indepen- 
dence, Coffeyville  and  Caney  had  to  some  noticeable  extent 
developed  along  a  given  line,  indicating  that  even  in  the  West 
as  in  the  East  the  "oil  lines"  held  good.  An  operator  of  note 
in  the  pioneer  days  of  Kansas,  a  man  by  the  name  of  Bloom, 
of  Pennsylvanian  experience,  electrified  his  credulous  auditors 
by  announcing  that  he  would  ship  an  outfit  over  to  Cleveland, 
Oklahoma,  and  drill  a  well.  He  proved  to  all  listeners  that 
the  oil  line  passed  near  Cleveland  as  it  plunged  its  way  south- 
ward out  of  Kansas.  He  did  move  over  to  the  new  location 
some  fifty  miles  southward,  and  did  actually  get  a  producing 
well.  Time  and  drilling  have  long  since  developed  the  knowl- 
edge that  it  was  by  the  merest  good  luck  that  the  new  location 
happened  to  be  on  a  good  anticline,  and  that  it  was  local  to 
the  Cleveland  area,  though  embracing  oil-making  and  oil- 
bearing  formations  of  great  regional  extent. 

Little  by  little  throughout  the  years,  developing  in  the  many 
oil-producing  regions  throughout  the  world,  information  ac- 
cumulated and  experiences  multiplied  to  the  point  of  convincing 
oil  operators  that  a  scientific  knowledge  of  the  character  of 
rocks  and  their  relative  position  in  the  earth  bear  a  most  inti- 
mate relation  to  the  possible  presence  or  absence  of  oil  in  a 
locality.  The  great  oil-producing  companies  first  employed 

68 


GEOLOGICAL  INFORMATION  ESSENTIAL 


geologists  to  determine  favorable  regions  where  test  drilling 
should  be  done.  Later  such  advice  was  sought  also  in  making 
new  locations  in  a  known  productive  field,  since  it  soon  became 
known  that  not  all  locations  upon  a  well-defined  oil  structure 
possessed  equal  opportunity  of  returning  large  quantity  oil 
output. 

Since  about  the  year  1900  no  serious  undertaking  in  the 
control  of  men  of  noteworthy  achievement  in  the  oil  business 
has  been  launched  without  the  counsel  of  geologists.  At  this 
time  if  one  were  to  institute  measures  looking  to  the  drilling  for 
oil  in  an  unknown  region,  and  did  not  include  an  exhaustive 
examination  of  the  ground  to  determine  its  oil-bearing  possi- 
bilities, the  men  of  successful  experience  in  the  industry  would 
refuse  to  impute  intelligence  or  honesty  to  the  undertaking. 

Even  with  the  facts  stated  being  constantly  before  us,  it 
appears  of  statistical  record  in  the  documents  of  the  United 
States  Geological  Survey,  the  Geological  Surveys  and  Mining 
Bureaus  of  various  of  the  States,  and  in  the  private  reports  of 
various  of  the  great  oil-producing  companies,  that  in  excess  of 
400  test  wells  are  drilled  every  year  throughout  the  country 
at  locations  which  have  not  had  the  benefit  of  intelligent  inves- 
tigation by  scientists  whose  opinions  are  worthy  of  confidence. 
It  follows  quite  naturally  that  an  excessively  small  percentage 
of  such  tests  result  in  discovering  oil. 

It  is  facts  of  the  character  stated  which  have  to  no  inappre- 
ciable extent  surrounded  the  oil-producing  industry  with  a  gen- 
eral mental  complex  which  embraces  every  conceivable  hazard. 
It  is  generally  thought  that  nothing  can  represent  a  danger  of 
loss  equal  to  the  peril  of  oil  drilling.  The  records  mentioned 
bear  out  the  opinion,  though  in  the  main  it  is  wrong. 

After  a  region  has  been  critically  examined  by  scientific 

69 


RECENT  CONSTRUCTIVE  LAWS 


investigators,  and  its  oil-bearing  possibilites  passed  upon  favor- 
ably, test  drilling  carried  on  at  the  indicated  locations  under 
the  direction  of  competent  managers  and  experienced  oil  drill- 
ers, has  been  found  to  result  in  discovering  oil  in  upward  of 
90  per  cent  of  the  tests.  When  such  test  drilling  is  done  at 
random,  without  the  benefit  of  a  favorable  report  from  com- 
petent advisers,  the  percentage  of  failures  is  probably  greater 
than  90  per  cent. 

Oil  promotions  which  have  been  rife  throughout  the  country 
for  a  period  of  twenty  years  induced  the  enactment  here  and 
there,  and  with  commendable  rapidity  in  logically  located  legis- 
lative bodies,  of  various  statutes  looking  to  the  protection  of 
the  legitimate  and  the  discouragement  of  the  irresponsible 
company  promoter.  While  it  appears  that  there  are  heard  from 
time  to  time  certain  criticisms  directed  at  laws  of  the  character 
mentioned,  it  is  the  experience  of  the  writer  that  almost  in- 
estimable good  has  been  achieved  by  the  efforts  to  curb  useless 
and  unwarranted  promotions,  especially  as  applied  to  the  oil 
industry. 

It  will  be  seen  that  there  would  grow  up  around  the  condi- 
tions which  would  evolve  from  the  laws  referred  to,  commonly 
called  "Blue-Sky  Laws";  the  industry  of  oil  drilling;  and  the 
province  of  the  geologist  as  an  economic  factor  in  the  business; 
a  situation  which  would  include  the  State  Department  charged 
with  the  administration  of  the  law,  the  driller,  promoter,  and 
the  geologist,  as  parties  to  any  new  oil  promotion.  These  con- 
ditions have  enforced  a  further  necessity  which  has  been  taken 
in  hand  by  various  organizations  of  professional  geologists, 
notably  in  the  direction  of  formulating  certain  categorical 
requirements  antecedent  to  accepted  professional  standing.  The 
American  Association  of  Petroleum  Geologists  is  one  of  the 

70 


GEOLOGISTS'  ORGANIZATIONS 


organizations  of  national  standing;  the  International  Geological 
Society  is  another;  the  Southwestern  Association  of  Petroleum 
Geologists,  largely  devoted  to  interests  lying  within  the  Mid- 
Coniinent,  Gulf  Coastal  and  Louisiana-Arkansas  fields,  is 
another  of  local  note.  At  this  time  a  movement  is  under  way 
to  organize  the  International  Pacific  Geological  Society  in 
California,  which  should  quite  fully  provide  for  adequate  rep- 
resentation of  professional  men  of  standing  in  the  lands  of  all 
Pacific  Ocean  shores. 

Many  of  the  State  Universities  have  added  teachers  to  their 
Geological  departments,  and  have  greatly  widened  and  ex- 
tended the  scope  of  the  scholastic  work,  making  special  pro- 
vision for  classes  in  oil  field  examination. 

It  is  by  such  processes  that  enterprise  joins  with  learning  in 
developing  sanely  the  leading  economic  resources  of  the  coun- 
try, and  in  doing  so  conforms  to  a  liberal  and  intelligent  appli- 
cation of  the  laws  governing  the  identification  of  funds  for  the 
purpose.  The  results  which  have  been  accomplished  by  the 
administrators  of  the  restrictive  statutes  defining  honest  and 
practicable  promotions  are  as  excellent  as  could  be  rightly  ex- 
pected from  efforts  undertaken  during  the  formative  stages  of 
such  activities.  Millions  of  dollars  have  been  saved  to  specu- 
lators by  reason  of  such  laws;  and  millions  in  addition  have 
been  saved  and  will  be  saved  to  them  when  it  is  generally 
known  that  geologists  of  standing  and  reputation  work  in 
harmony  with  such  State  officers. 

It  appears  practicable  to  suggest  that  amendments  to  the 
laws  mentioned  in  many  of  the  States  might  be  enacted  to 
include  a 'complete  and  readily  verifiable  statement  of  the  entire 
purposes  of  the  promoters,  not  only,  but  a  copy  also  of  a  geo- 
logical report  upon  the  area  proposed  for  drilling  made  by  a 

71 


OIL  COMPANY  PROMOTION 


geologist  of  standing,  all  to  be  supplied  to  the  administrative 
department  having  charge  of  the  province  of  the  law.  This 
simple  addition  to  the  laws  would  in  many  cases  operate  to 
prohibit  drilling  in  new  and  untried  regions  where  competent 
knowledge  of  the  formations  and  structure  would  perforce 
advise  against  it.  In  addition,  it  would  have  the  beneficial 
effect  of  serving  favorably  the  proper  interests  of  legitimate  and 
honest  efforts  in  opening  new  fields. 

Quite  often  the  very  interesting  question  recurs  that  geolo- 
gists might  refuse  to  make  investigations  in  regions  known  to 
them  to  be  wholly  unfavorable  for  oil.  Also,  that  they  might 
well  withhold  their  professional  services  from  men  or  companies 
that  cannot  make  a  proper  showing  of  intention  and  record. 
Neither  would  be  practicable  or  in  good  practice.  The  sur- 
geon asks  no  questions  with  respect  to  the  causes  of  injury 
before  operating,  unless  he  knows  that  penal  laws  have  been 
violated;  even  then  he  operates  and  discloses  the  facts  to  the 
authorities  afterward.  The  lawyer  asks  no  questions  relative 
to  the  standing  of  his  client  if  the  proper  fee  and  a  right  issue 
are  offered,  except  that  he  really  has  knowledge  of  law  viola- 
tion. The  subject  is  one  of  an  ethical  character,  and  must  be 
answered  by  the  geologist  as  it  is  answered  by  men  of  other 
professions;  that  is,  Is  the  thing  offered  honorable  and  of  good 
report?  The  surgeon's  knife  has  at  times  uncovered  the  seat 
of  trouble  where  it  was  not  suspected,  as  the  geologist  has  found 
adequate  evidences  of  oil  accumulation  in  areas  which  he  had 
previously  supposed  to  be  unfavorable. 

However,  the  fact  must  not  be  lost  sight  of  that  there  is  no 
man  of  greater  value  to  a  community  than  a  capable,  conscien- 
tious promoter.  It  is  during  the  period  only  before  success 
has  followed  his  efforts  that  his  methods  are  questioned,  or  his 

72 


CONDITIONS  GROWING  BETTER 


objects  and  purposes  are  adversely  scrutinized.  After  the  in- 
itial success,  and  after  there  develops  from  his  activities  profit- 
paying,  stable  enterprises  resulting  in  general  good,  is  he 
admitted  to  the  inner  circles  of  solid  business.  One  should  not 
quarrel  with  that  fact;  it  is  a  situation  no  amount  of  discussion 
will  change.  There  may  be  cases  where  the  restrictions  of  the 
laws  and  the  regulations  of  commissions  appear  to  render  more 
difficult  the  speedy  accomplishment  of  a  worthy  promotion;  but 
it  should  be  borne  in  mind  that  such  conditions  also  operate  to 
remove  from  the  field  many  who  would  take  advantage  of  the 
absence  of  such  restrictions  and  such  regulations. 

During  the  past  few  years  the  writer  has  observed  that  there 
is  a  rapidly  growing  sentiment  among  promoters  everywhere  to 
more  fully  and  definitely  trim  their  activities  to  the  strict  ethics 
of  speculation,  and  to  so  order  their  promotions  as  to  actually 
give  the  people  who  supply  the  funds  a  square  deal  and  a 
clean  run  for  their  money.  It  has  been  noted  further  that  few 
will  complain  of  having  lost  their  money  if  they  realize  that 
they  have  been  treated  fairly,  and  have  had  to  contend  only 
with  the  hazards  nearly  always  present  in  any  enterprise  which 
offers  the  possibilities  of  very  big  profits  in  a  comparatively  short 
time.  It  is  when  a  stockholder  believes  he  has  not  had  an 
honest  chance  that  he  will  complain,  and  very  justly  so. 

The  blue-sky  laws  are  day  by  day  making  it  safer  and 
better  for  the  honest  promoter  to  successfully  launch  and  com- 
plete his  enterprise,  and  day  by  day  more  difficult  for  the 
unscrupulous  promoter. 


73 


LETTER  FROM  DR.  GEORGE  H.  HOOK,  GEOLO- 
GIST, REQUESTING  THE  AUTHOR  TO  INCLUDE 
CHAPTER  IX  IN  THE  BOOK 

SAN  FRANCISCO,  CALIFORNIA, 

FEBRUARY,  1922. 
Dr.  Edward  Allison  Hill, 
San  Francisco,  California. 
DEAR  DOCTOR  HILL: 

The  writer  has  been  afforded  great  pleasure  by  availing  him- 
self of  the  privilege  extended  by  you  to  read  the  proof  sheets 
of  the  entertaining  and  instructive  matter  in  GEOLOGICAL 
NOTES  ON  OIL  STRUCTURES. 

While  the  epitome  of  geologic  history  gathered  into  the  brief 
compass  of  an  article  written  for  the  Fort  Worth  Star-Telegram, 
which  treats  in  a  masterly  fashion  the  fascinating  subject  of  suc- 
cessive formations  for  millions  of  years  as  they  are  found  under- 
lying Tarrant  County,  Texas,  might  not  be  thought  cognate  to 
the  matter  of  the  book,  it  would  be  a  real  loss  not  to  incorporate 
that  profound  study  as  a  part  of  your  delightful  analyses  of  earth 
forms  and  oil  structures.  It  deserves  a  place  in  a  work  of  per- 
manent value,  and  in  that  form  it  will  add  to  the  interest  of  the 
reader  while  it  impresses  him  with  the  knowledge  that  you  are 
in  full  possession  of  the  abstruse  as  well  as  the  simple  elements 
of  your  profession. 

The  writer  adopts  this  opportunity  of  again  expressing  to 
you  his  appreciation  of  the  honor  of  reading  your  book  before  its 
publication,  and  wishes  to  suggest  that  the  layman  will  find  in 
your  work  a  most  pleasing,  direct  and  forceful  exposition  of  the 
subjects  treated.  Interesting  and  instructive  books  are  rarely 
found  which  cover  so  fully  and  in  such  every-day  language  any 
of  the  deeper  and  more  technical  aspects  of  the  many  departments 
of  any  economic  science;  your  book  achieves  such  objects  in  a 
very  happy  manner. 

I  have  the  honor  to  remain 

•  Fraternally  and  sincerely, 

GEORGE  H.  HOOK, 

GHH-S  Geologist. 

75 


CHAPTER  IX 

(Requests  of  many  friends  of  the  author  to  include  the  fol- 
lowing article  is  complied  with.  It  first  appeared  in  the  Fort 
Worth  Star-Telegram,  of  Fort  Worth,  Texas,  Sunday,  May  8, 
1921.— Ed.) 

TARRANT  COUNTY  GEOLOGICAL  HISTORY 
REVEALED  BY  DRILL 


IN  PERIOD  OF  1 0,000,000  YEARS  BOTH  LAND  AND  SEA 
EXISTED  HERE — SOME  QUEER  ANIMALS 


By  EDWARD  A.  HILL 

DEEP  well  drilling  in  Tarrant  County  has  revealed  the  geo- 
logical structures  upon  which  Fort  Worth's  skyscrapers 
have  been  built  as  well  as  the  prehistoric  record  of  this  section. 
Cuttings  through  the  various  formations  take  us  back  ten 
million  years  or  more. 

The  sands,  limes  and  shales  that  have  been  uncovered  by  the 
drill  in  the  Burchill  well  in  Polytechnic  recount  eras  of  hot 
deserts,  the  submerging  of  waters  of  cold  and  warm  seas  and 
alternating  ages  of  arctic,  tropic  and  temperate  climates. 

Cuttings  from  the  Aledo  well  and  from  other  deep  borings 
in  counties  west  of  Tarrant  supply  evidence  that  monstrous 
creatures  roamed  or  waddled  awkwardly  over  the  land  or  slid 
slimily  into  seas  of  an  ancient  world.  These  wells  also  tell  of 
profuse  and  entangled  verdure. 

76 


SEA  LIFE  CAME  FIRST 


No  species  of  plant  or  animal  ever  has  returned  after  once 
it  passed.  Nature  cleared  the  page  as  one  erases  figures  from 
a  slate  when  once  the  infinite  object  of  life  was  achieved. 

First  were  the  Azoic  rocks,  void  of  organism,  lying  doubtless 
7,000  to  1 0,000  feet  under  the  pavements  of  the  city.  No 
drill  near  Tarrant  has  penetrated  to  their  great  depth.  But 
we  believe  they  are  there  because  in  other  places  we  find  them 
lying  under  formations  which  are  here.  Over  Azoic  are  rocks 
called  the  Proterozoic  formations,  which  contain  traces  of 
organic  life. 

SEA  LIFE  FIRST 

After  that  are  other  series  called  Paleozoic  rocks,  meaning 
ancient  life  formations.  No  hint  of  any  land  life  has  been 
found  in  them.  Evidently  living  organism  passed  all  or  nearly 
all  of  its  life  in  the  waters  that  formed  the  seas  of  those  ages. 

The  succeeding  era  was  the  Mesozoic,  the  last  one  before  the 
era  in  which  we  live,  the  Cenozoic.  Some  have  liked  to  say 
we  live  in  the  Quaternary.  We  live  in  the  early  part  of  the 
Cenozoic — probably  the  spring  season  of  it. 

At  the  opening  of  the  Paleozoic  we  find  the  oldest  known 
normal  fossils,  and  we  know  that  they  are  at  very  great  depth 
under  Fort  Worth.  Before  that  time  billions  of  varied  genera 
and  species  lived  in  the  waters.  Throughout  the  last  named 
period,  and  in  the  Ordovician  and  Silurian,  the  two  next  suc- 
ceeding periods,  what  we  call  Cystoids  (stone  lilies)  grew  in 
the  seas  and  upon  their  bottoms  in  immense  profusion.  Their 
remains  have  in  some  places  made  great  bodies  of  limestone. 
Also  there  were  marine  scorpions  not  unlike  their  stinging  pos- 
terity of  today,  some  of  them  attaining  nine  feet  in  length. 
Fossils  of  the  latter  have  been  found  in  the  limestones  of  Travis 
County.  In  early  Cambrian  times  nearly  all  of  Texas  was  dry 

77 


STRANGE  ANIMAL  LIFE 


land.      In  late  epochs  of  that  period  a  sea  covered  the  State 
and  adjoining  regions. 

ARMOUR  BEARING  ANIMALS 

In  sea  life  the  mollusks  and  arthropods  were  legion.  Trilo- 
bites  rolled  up,  unrolled  and  scuttled  away  from  the  bigger  and 
more  active  Cephalopods,  other  armour-bearing  marine  ani- 
mals. Famous  slate  quarries  in  Wales  and  in  New  York  and 
other  places  are  in  rocks  of  Cambrian  age. 

Then  came  the  Ordovician  age  (Lower  Silurian),  during 
which  the  nearest  land  surfaces  to  what  is  now  Tarrant  County 
were  islands  extending  chainlike  from  Wyoming  to  Arizona, 
and  in  what  we  know  as  the  Ozark  region  in  Missouri  and 
Oklahoma.  A  great  authority  has  said  that  upward  of  1 ,600 
classified  species  of  animals  are  known  from  the  Middle  Ordo- 
vician alone. 

In  the  Upper  Silurian  limestones  we  find  that  Crinoids  be- 
came so  prolific  that  they  formed  veritable  flower  gardens  in 
the  seas.  Horned  crawfish-looking  fish,  some  with  hook-shaped 
beaks,  were  in  the  waters.  Probably  sharks  of  primitive  type, 
among  the  first  vertebrates,  were  also  in  the  waters. 

STRATA  HERE  UNTAPPED 

But  none  of  the  drills  near  Tarrant  have  penetrated  to  the 
depths  of  the  foregoing  forms;  nor  have  they  reached  the  for- 
mations made  under  a  later  and  much  more  extensive  sea,  the 
Devonian.  Yet  it  is  probable  that  in  the  midst  of  that  period 
the  seas  withdrew  from  a  considerable  of  the  land  area  of 
Texas,  and  that  Tarrant  County  and  large  adjacent  regions 
were  dry  land. 

The  seas  of  the  Mesozoic  era  possibly  came  nearly  to  North 
Fort  Worth.  Great  fishes  like  sea  cows  ground  their  food  with 

78 


EARLY  LAND  AND  SEA 


a  side  wise  motion  of  the  jaws,  gyratory,  somewhat  as  cud- 
chewing  animals  do  now. 

In  the  earlier  period,  the  Mississippian,  nearly  all  of  North 
America  was  submerged  by  waters.  Drill  holes  not  far  from 
Tarrant  have  penetrated  to  rocks  of  that  age,  hard,  crystalline, 
massive. 

About  140  miles  northward  an  island  was  formed  then  by 
an  upthrust  of  the  strata,  the  upheaval  releasing  to  the  flood 
vast  quantities  of  sulphurous,  iron-bearing  waters.  The  Ar- 
buckle  mountains  were  made  at  that  time.  But  before  the  end 
of  the  period  the  waters  withdrew  from  many  localities  and  the 
exposed  rocks  were  denuded  by  erosion.  We  know  that  there 
are  hills,  ridges,  valleys  and  great  tilted  sub-surface  areas  that 
were  the  result  of  the  wastage  wrought  by  the  elements  and  the 
buckling  strata.  The  drills  have  shown  this  in  many  places. 

MINERALS  OF  MISSISSIPPIAN 

Many  animals  survived  from  the  Devonian  to  the  Missis- 
sippian, and  flourished  throughout  the  latter,  multiplying  and 
developing.  Many  and  varied  values  of  an  economic  kind  are 
taken  from  rocks  of  that  age.  Much  of  the  oil  in  the  Eastern 
States  and  some  of  it  in  Kansas  and  Oklahoma  come  from  for- 
mations of  that  series.  Vast  quantities  of  salt  are  pumped 
from  them,  and  zinc  and  lead  are  found  in  their  later  members 
in  Missouri,  Kansas  and  Oklahoma.  Great  cup-like,  flower- 
appearing  corals  of  that  age  were  in  abundance.  Ivory-like, 
bead-shaped  embedded  heads  of  Crinoids,  beautiful  sea 
growths  of  lime,  are.  nearly  the  entire  component  of  many  beds 
of  limestone  of  that  period.  Their  growth  must  have  been 
widespread  and  excessive. 

Of  the  vertebrates,  the  shark  shows  the  greatest  development 

79 


COAL  FORMING  PLANTS 


from  Devonian  times;  it  grew  very  big  and  was  very  fierce  and 
bloodthirsty,  but  without  anything  like  a  living  man  to  eat. 

In  the  Pennsylvanian  period,  the  great  middle  series  of  the 
Carboniferous  age,  we  are  nearer  home  as  to  depth,  but  long 
ages  removed  in  time. 

It  is  near  us  in  depth  under  our  streets.  If  we  were  to  dig 
a  hole  fifteen  times  deeper  than  our  tallest  skyscraper  is  high, 
the  bottom  might  be  upon  the  formations  of  Pennsylvanian  age. 
The  waters  over  this  region  then  formed  great  bodies  of  lime- 
stone, shale  and  sand  rock,  beating  for  hundreds  of  thousands 
of  years  against  the  walls  of  the  Arbuckles,  which  were  formed 
in  an  earlier  age  1 40  miles  north  of  Tarrant  County. 

Plant  life  was  far  more  prolific  then  than  in  any  previous 
period.  Our  present  ground  pines  are  direct  lineal  descendants 
of  plants  of  that  age.  Their  ancestors  we  call  Lycopods. 
What  are  known  as  Equisetas,  our  present  horsetails,  growing 
along  creeks  and  ditches,  were  also  representative  of  Lycopodian 
vegetation. 

SWAMP  OF  FORESTS 

Over  in  the  region  of  Bridgeport  and  in  Palo  Pinto  County 
and  Jack,  and  in  the  numerous  places  where  we  now  mine  coal, 
vegetable  growth  of  the  character  mentioned  must  have  been  in 
bewildering  swamp  forests.  Our  coal  measures  are  made  of 
them  and  kindred  plant  life.  What  we  call  Cordaites  grew 
in  swamp  and  marsh  lands  in  impenetrable  profusion,  for  we 
find  their  remains  in  our  coal  bodies  in  vast  amount.  Some- 
times they  were  50  to  100  feet  high,  their  diameters  from  two 
to  five  feet,  their  leaves  from  five  to  six  feet  long  and  as  many 
inches  wide.  Certain  of  their  species  are  called  Sigillarians, 
meaning  seal-trees,  so  called  because  their  trunks  bore  seal-like 
impressions  running  spirally  around  them. 

80 


MONSTROUS  BEASTS 


Now,  at  about  the  time  of  the  ending  of  the  period  a  vast 
sea  of  blood-red  waters  came  to  the  shores  where  Weather- 
ford  now  is.  We  know  its  place  in  geological  history  as  the 
Permian  period.  The  great  ranch  country  of  Texas  is  upon 
earth  deposited  during  that  period.  It  was  made  throughout 
a  transition  stage  between  the  Paleozoic  and  Mesozoic  eras. 
Plant  life  was  more  scant,  which  means  that  animal  life  was 
not  so  varied  or  so  extensive  as  during  the  Pennsylvania!!. 

True  reptiles  of  monstrous  size  and  great  beasts  which  de- 
veloped out  of  the  lesser  species  of  earlier  times,  were  to  be 
seen  along  the  shores  of  the  red  seas.  The  waters  spread  north- 
ward as  far  as  Idaho,  southward  into  what  is  now  Mexico  and 
westward  to  New  Mexico.  But  it  is  not  quite  true  to  speak 
of  this  widespread  water  as  a  sea,  as  it  consisted  of  great  lakes, 
rivers,  shallow  and  deeper  bodies  of  water  in  its  later  epochs. 
HEAVY,  AWKWARD  BEASTS 

Where  we  now  live,  snake-like  beasts  with  sharp  teeth,  long, 
cumbrous  tails  and  short,  heavy  legs,  waddled  in  the  soft  muds 
of  the  shore  and  over  the  semi-arid  lands.  Upon  the  bottoms 
of  the  water  bodies,  as  well  as  during  the  following  periods,  the 
Triassic  and  Jurassic,  great  deposits  of  gypsum  and  salt  and 
dolomite  were  made.  We  are  plastering  and  whitening  the 
walls  of  our  homes  with  the  first,  sometimes  building  them  of 
the  last  and  seasoning  our  food  and  feeding  our  cattle  with  the 
other. 

The  Permian  period  ended  with  a  great  physical  disturbance. 
What  is  called  the  Appalachian  Revolution  occurred  then.  By 
its  action  there  were  bofn  the  mountains  of  that  name  in  Eastern 
United  States,  and  the  Ouchita  Mountains  of  Oklahoma  and 
Arkansas  were  then  strung  in  zigzag  along  the  horizon  to  define 
Homer  and  Caddo  and  other  oil  fields.  The  region  of  Tarrant 
County  remained  dry  land.  . 


THE  FIRST  BIRDS 


ANIMALS  OF  PERMIAN  AGE 

Though  the  animals  of  the  Permian  were  often  clumsy, 
clinging  to  and  bending  down  the  branches  of  trees  to  eat  the 
foliage ;  in  the  Triassic  and  Jurassic,  they  were  huge  and  fierce. 
The  nearest  shores  of  the  Triassic  sea  were  about  the  vicinity 
of  Bluffdale,  and  some  of  the  blundering  creatures  with  arm- 
like,  nimble  front  legs,  doubtless  had  habitat  where  now  flows 
the  Paluxi  River.  Mostly  the  land  surfaces  in  the  southwestern 
regions  of  the  United  States  were  desertlike  during  that  period, 
the  climatic  conditions  arid.  Yet  in  Arizona,  in  what  we  call 
the  Petrified  Forests,  there  are  tree  trunks  100  feet  long  and 
ten  feet  in  diameter,  dating  back  to  the  Triassic.  Such  trees 
grew  near  water  or  during  a  less  dry  epoch.  In  Erath  County 
not  more  than  forty  miles  from  Forth  Worth  there  are  great 
tree  trunks,  silicified,  heavy,  solid  rock,  that  are  part  Cretaceous, 
but  probably  also  part  Triassic.  What  we  know  as  Cycad 
trees  grew  then  as  they  now  grow  in  Mexico. 

FIRST  FEATHERED  BIRDS 

The  first  feathered  birds  known  to  the  earth  came  then. 
There  had  been  great  flesh-eating,  ravenous,  smooth-skinned, 
birdlike  reptiles,  reptilian-birds,  in  the  world  for  long  periods, 
but  no  feathered  songsters.  Moisture  increased  during  the  latter 
'part  of  the  period  and  the  balmy  air  and  greater  dampness 
clothed  the  vast  Western  and  Northwestern  plains  with  verdure. 

In  excavations  for  our  tall  buildings,  in  the  railway  cuts, 
along  the  deep  channels  made  here  and  there  by  Trinity  River, 
are  to  be  seen  the  layers  of  rocks  of  Cretaceous  age.  Towards 
the  Gulf  of  Mexico  these  rocks  are  covered  by  formations  of 
later  periods.  At  Galveston,  drills  have  shown  that  there  are 
later  deposits  of  3,000  feet  in  thickness.  Though  our  homes 

82 


SOME  TEXAS  FORMATIONS 


are  built  upon  the  solid  foundation  of  the  Cretaceous  period, 
we  are  surely  removed  from  it  by  something  like  a  million  years. 

Throughout  the  period  there  was  an  extensive  sea  connecting 
what  are  now  Gulf  waters  with  the  oceanic  basins  of  the  Arctic 
region.  Tarrant  County  is  about  1 40  miles  south  of  its  north- 
eastern shores,  which  bent  northwesterly  and  then  northward 
toward  the  pole.  Under  that  water  in  this  area  thick  sand 
deposits  were  put  down.  We  know  these  deposits  as  the  Trinity, 
Woodbine  and  other  sands.  Afterward  were  earth  movements 
which  depressed  the  bottom  of  the  sea  and  limestones  of  great 
thickness  were  deposited.  We  call  that  the  Fredericksburg 
lime.  Later,  what  we  know  as  the  Austin  chalk  was  put  down, 
far  from  shore.  Its  purity  and  freedom  from  wastage  carried 
away  from  land  masses  prove  that. 

CRETACEOUS  OIL 

In  the  Cretaceous  much  oil  and  gas  have  been  found,  and 
without  question  vastly  greater  quantities  will  yet  be  developed. 
The  fields  at  Beaumont  and  Corsicana,  and  later  at  Mexia,  are 
producing  from  rocks  of  that  age.  Some  have  thought  that 
there  are  very  good  reasons  for  believing  that  profitable  fields 
will  be  found  in  formations  of  that  age  near  Fort  Worth. 

What  is  called  the  Rocky  Mountain  Revolution  occurred 
during  the  ending  epochs  of  the  Cretaceous  period.  The  fold- 
ing and  the  buckling  of  the  rocks  of  western  North  America, 
the  Isthmus  and  South  America  happened  then.  The  turmoil 
traveled  from  Alaska  to  Cape  Horn,  in  some  places  upturning 
strata  20,000  feet  in  thickness.  Mountain  chains  were  made 
with  peaks  sometimes  as'  much  as  fifteen  miles  high. 
VOLCANIC  ERUPTIONS 

Far  towards  the  northwest  was  a  red  flare  of  light  reflected 
by  the  dust-filled  air  near  where  are  now  Rabbit  Ear  Mount- 

83 


GREAT  ANCIENT  SEAS 


ains  in  northern  New  Mexico.  There  were  volcanic  eruptions 
near  there  then.  The  Black  Mesa  is  there  today,  a  lava  flow 
formation. 

At  that  time  Tarrant  County  was  covered  with  sea  water, 
but  it  was  not  very  distant  from  the  northerly  shore.  The 
whole  firmament  was  filled  with  fine,  suffocating  dust,  blown 
about  thousands  of  miles  by  the  contrary  and  shifting  winds. 
The  logs  of  wells  have  disclosed  such  conditions. 

The  eruptions  continued  throughout  the  succeeding  period, 
the  Tertiary.  The  infusion  of  volcano  waters  and  gases  into 
the  seas,  and  the  breaking  up  of  the  solid  foundations  of  the 
earth  in  so  many  places  and  at  such  widely  separated  localities, 
resulted  in  great  changes  in  the  existing  forms  of  animal  and 
vegetable  life. 

At  first  Tarrant  County  was  some  300  miles  north  of  the 
more  northerly  shores  of  the  Tertiary  waters.  Later  it  was 
about  midway  between  a  great  epicontinental  sea  toward  the 
northwest  some  250  to  300  miles,  and  another  southeasterly 
nearly  an  equal  distance,  but  the  area  of  Fort  Worth  was  land. 
To  be  sure  it  was  a  land  of  many  lakes  and  rivers,  marsh  and 
swamp  and  slough  and  embayment,  a  soggy  land.  Also,  it 
was  a  warm  country.  Fossils  are  in  abundance  and  are  satis- 
fyingly  accurate  in  denoting  a  warm  climate  even  to  the  north- 
ern boundaries  of  the  United  States.  Figs,  palms  and  magnolias 
grew  over  the  Great  Plains. 

LIFE  FORMS  CHANGE 

But  all  life  forms  had  undergone  bewildering  changes. 
Many  forms  took  on  grotesque  shapes,  struggling  with  the  sul- 
phurous waters  and  the  gaseous  air  to  adapt  themselves  to 
swiftly  altering  conditions. 

What  we  now  know  as  the  Glacial  periods  fell  athwart  the 

84 


PAST  AGES  OF  ICE 


hemispheres  during  the  times  named.  During  a  part  of  the  ice 
epochs  we  know  that  the  ice  sheets  extended  as  far  south  as 
Texas,  and  irregularly  to  about  that  latitude  across  the  con- 
tinent. Across  Northern  Kansas  and  in  Illinois  and  Indiana, 
where  the  debris  is  accumulated  in  most  pronounced  dunes, 
terraines,  ridges  and  mounds,  we  easily  and  certainly  trace  the 
approximate  southern  margin  of  the  vast  ice  sheets.  Their 
melting  dropped  down  boulders  and  gravels  carried  in  the  ice 
from  Labrador  and  Greenland  and  from  other  far  northern 
Laurentian  rock  lands. 

The  last  glaciation  was  something  like  35,000  years  ago. 
It  had  a  relaxing  effect  upon  the  meteorological  conditions  of 
Tarrant  County.  The  climate  was  temperate  and  every  variety 
of  vegetation  multiplied  and  increased.  Probably  it  was  earlier 
than  the  last  epoch  that  Mastodonic  tribes  of  great  beasts,  called 
proboscidians,  roamed  about  in  the  thick  wooded  bottoms  of 
the  Trinity,  the  Brazos  and  the  Colorado  Rivers.  In  the 
Carnegie  Library  at  Fort  Worth  are  a  pair  of  ivory  tusks  that 
were  found  in  a  gravel  pit  southwest  of  the  city  a  few  miles. 
These  are  but  a  specimen  among  many  that  are  like,  and  very 
many  that  are  different,  which  represent  other  parts  of  the 
skeleton  build  of  these  and  other  great  animals  making  their 
homes  in  Texas  then. 


85 


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ICT 


1939 


•  » 


LD  21-95m-7,'37 


YB   1256 


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